Biology subjects

Van Rompay, K. K. A.

Publications and source records attributed to Van Rompay, K. K. A..

At least 19 recordsLinked to original sources

bioRxiv2026

Designed nanofiber immunogens prime antibody responsesto diverse conformations of the HIV-1 fusion peptide

Focusing antibody responses towards known neutralizing epitopes is a major strategy for protective immunization. Targeting flexible antigenic regions represents a unique challenge because functional antibodies must be able to bind the epitope of interest in multiple conformations. The fusion peptide (FP) of HIV-1 is a flexible peptide critical to viral entry of host cells for which broadly neutralizing antibodies have been identified. Because elicitation of potent, functional antibodies toward this epitope remains an unmet challenge in HIV-1 vaccination, we introduce a designed immunogen platform capable of raising anti-FP-antibodies with increased conformational tolerance relative to a traditional carrier protein. Antibodies induced by these immunogens bind heterologous FP sequences when elicited in mice and infant non-human primates. This platform shows promise for preclinical development to prime antibody responses toward FP of the HIV-1 envelope and can likely be translated to peptide immunofocusing for other viral pathogens.

bioengineering↗

bioRxiv2025

Germline-targeting HIV Envelope SOSIP immunization more frequently elicits broadly-neutralizing antibody precursor responses in infant compared to juvenile rhesus macaques

A vaccine capable of inducing broadly neutralizing antibodies (bnAbs) is essential for effective prevention against HIV in children and adolescents. Germline-targeting vaccine strategies aim to stimulate bnAb precursor B cells through carefully designed immunogens, such as the stabilized SOSIP trimers, which mimic native HIV envelope (Env) proteins while presenting key neutralizing epitopes to germline B cell receptors. Given the ability of children living with HIV to develop bnAbs earlier and at a higher frequency than adults, we compared the immunogenicity of a CD4 binding site (CD4bs) bnAb germline-targeting SOSIP trimer immunization strategy in infant (n = 5) and juvenile (n = 4) rhesus macaques (RMs). Animals received 3 doses of the germline-targeting BG505 GT1.1 immunogen, followed by 3 boosts of wild-type BG505 SOSIP, each adjuvanted with the TLR7/8 agonist, 3M-052-SE. After 1.5 years, the RMs were further boosted with a mixed clade B Env trimer nanoparticle to enhance heterologous virus neutralization responses. This germline-targeting strategy induced equivalent titers of neutralizing antibodies in both groups of RMs, yet the infants exhibited a higher magnitude of vaccine-specific IgG binding. Notably, after 3 doses of BG505 GT1.1 SOSIP, infants had higher BG505 GT1.1-specific IgD- B cells. Upon completion of the vaccine regimen, 4 of 5 infants developed a CD4bs bnAb precursor response detectable in serum compared to only 1 of 4 juveniles. Finally, administration of the mixed clade B nanoparticle was able to increase the breadth of antibody responses in 3 of 5 infants and 2 of 4 juveniles. These results suggest that immunization in early-life may enhance bnAb induction and highlight the potential for future pediatric HIV-1 vaccine strategies. Author SummaryVaccines that can generate antibody responses that have breadth and potency in neutralization can protect children and adolescents from acquiring multi-strain viruses like HIV. Increasingly, vaccine strategies have become better tailored to elicit these broadly neutralizing antibodies (bnAbs), such as the germline-targeting HIV envelope antigens, which have shown great promise. To determine if we could elicit protective antibody responses against HIV in early life, we immunized infant and juvenile monkeys using the same vaccine strategy. In this study, we found that while both infants and juveniles developed similar levels of antibodies that could neutralize HIV, the infants showed stronger antibody responses in several key areas. Moreso, infants developed the type of early antibody response that researchers believe is needed to eventually evolve into broadly neutralizing antibodies. These findings suggest that initiating HIV vaccination earlier in life may offer a better chance at generating the bnAbs needed to protect against various HIV strains. Our work highlights the potential benefits of initiating an HIV vaccine regimen in childhood.

immunology↗

bioRxiv2025

Rhesus macaques model human Mayaro virus disease and transmit to Aedes aegypti mosquitoes

BackgroundMayaro virus (MAYV) is a mosquito-borne alphavirus endemic to Latin America that causes fever and arthritis. Unlike the related chikungunya virus, MAYV has not caused widespread, human-amplified epidemics. One possible explanation is that human viremia levels are too low to support transmission to urban Aedes (Stegomyia) aegypti mosquitoes. We used rhesus macaques (RM) to model human-to-Ae. aegypti transmission and to further expand understanding of their relevance to human MAYV disease. Methodology/Principal FindingsTwelve RM were inoculated with a genotype D lineage MAYV strain using one of 3 doses: 7 log10 plaque forming units (PFU) intravenously (IV), 7 log10 PFU subcutaneously (SC), or 3 log10 PFU SC. Viremia was measured daily in plasma and RM were euthanized 10- or 12-days post-inoculation (dpi). On 2, 3, 5, and 7 dpi, Ae. aegypti were allowed to bloodfeed, incubated for 10 days, then dissected and tested to detect MAYV in tissues and saliva. RM developed infectious MAYV viremias lasting 3 days, peaking 1-2 dpi with titers ranging from 2-6 log10 PFU/ml. RM inoculated with 7 log10 PFU IV developed significantly higher viremias (area under the curve) than those receiving 3 log10 PFU SC. MAYV RNA was detected in muscle, lymphoid, central nervous, and cardiac tissues. RM showed no signs of fever or joint swelling but some developed mild rashes in areas distant from mosquito feeding sites and histologic inflammation was observed in joints and muscles. Only Ae. aegypti that fed on viremic RM 2 dpi became infected, with an overall infection rate of 48%. Among all mosquitoes that fed on RM 2 dpi, only 2% (4/217) had infectious MAYV in their saliva, suggesting transmission competence. Despite 11 of 12 RM transmitting MAYV to at least one mosquito, individual RM varied in infectiousness to Ae. aegypti, and mosquito cohort infection rates did not correlate with RM viremia levels. Conclusions/SignificanceRM exhibit short-lived MAYV viremias, broad tissue tropism, and mild joint and muscle inflammation, closely resembling human infection. While viremic RM can infect Ae. aegypti, the transmission window is narrow and transmission by Ae. aegypti is rare. The combination of a short infectious period in RM and low transmissibility of Ae. aegypti infected from RM may help explain the absence of widespread urban MAYV outbreaks. AUTHOR SUMMARYMayaro virus (MAYV) is a mosquito-borne virus found in Latin America that causes fever and joint pain, similar to chikungunya virus (CHIKV). However, unlike CHIKV, MAYV has not led to large outbreaks. One reason may be that levels of MAYV in human blood are too low for Aedes aegypti mosquitoes--known for spreading chikungunya, dengue, and Zika--to pick up and transmit the virus in cities. To better understand this, we studied rhesus macaques, a monkey species that serves as a model for how MAYV behaves in people. We tracked virus levels in their blood and tissues and observed mild joint and muscle inflammation, similar to Mayaro fever in people. Although the macaques were able to infect some Ae. aegypti mosquitoes, the transmission window was short, and only a few mosquitoes that became infected had virus in their saliva, suggesting transmission competence. This limited ability of urban mosquitoes to spread MAYV may help explain why major outbreaks have not occurred.

microbiology↗

bioRxiv2024

Dose-dependent regulation of immune memory responses against HIV by saponin monophosphoryl lipid A nanoparticle adjuvant

The induction of durable protective immune responses is the main goal of prophylactic vaccines, and adjuvants play an important role as drivers of such responses. Despite advances in vaccine strategies, a safe and effective HIV vaccine remains a significant challenge. The use of an appropriate adjuvant is crucial to the success of HIV vaccines. Here we assessed the saponin/MPLA nanoparticle (SMNP) adjuvant with an HIV envelope (Env) trimer, evaluating the safety and impact of multiple variables including adjuvant dose (16-fold dose range), immunization route, and adjuvant composition on the establishment of Env-specific memory T and B cell responses (TMem and BMem) and long-lived plasma cells in non-human primates. Robust BMem were detected in all groups, but a 6-fold increase was observed in the highest SMNP dose group vs. the lowest dose group. Similarly, stronger vaccine responses were induced in the highest SMNP dose for CD40L+OX40+ CD4 TMem (11-fold), IFN{gamma}+ CD4 TMem (15-fold), IL21+ CD4 TMem (9-fold), circulating TFH (3.6-fold), bone marrow plasma cells (7-fold), and binding IgG (1.3-fold). Substantial tier-2 neutralizing antibodies were only observed in the higher SMNP dose groups. These investigations highlight the dose-dependent potency of SMNP in non-human primates, which are relevant for human use and next-generation vaccines.

immunology↗

bioRxiv2024

Commensal bacteria inhibit viral infections via a tryptophan metabolite

Clinical outcomes following viral exposures exhibit substantial interindividual variability. Although developing evidence suggests commensal bacteria modulate viral infections, the specific bacteria and mechanisms remain underexplored. Here we define a pathway by which viral infections are inhibited by specific tryptophan-catabolizing bacteria. Using HIV as a model, we bioinformatically associated and experimentally validated several bacterial species that inhibited viral replication. This activity required the aromatic amino acid aminotransferase (ArAT) to metabolize tryptophan into 3-indolelactic acid, which agonizes the aryl hydrocarbon receptor (AhR). Given that AhR regulates multiple viral infections, we found that commensal bacteria also inhibit cytomegalovirus (CMV) in an ArAT-dependent manner. Finally, we confirmed that ArAT is associated with protection against disease outcomes in three distinct human cohorts at-risk for HIV, CMV, or symptomatic COVID-19. Taken together, our results provide mechanistic insight into how commensal bacteria impact viral infections, thereby adding to an emerging field focused on host-commensal-virus interactions.

microbiology↗

bioRxiv2024

Discovery and engineering of the antibody response against a prominent skin commensal

The ubiquitous skin colonist Staphylococcus epidermidis elicits a CD8+ T cell response pre-emptively, in the absence of an infection1. However, the scope and purpose of this anti-commensal immune program are not well defined, limiting our ability to harness it therapeutically. Here, we show that this colonist also induces a potent, durable, and specific antibody response that is conserved in humans and non-human primates. A series of S. epidermidis cell-wall mutants revealed that the cell surface protein Aap is a predominant target. By colonizing mice with a strain of S. epidermidis in which the parallel {beta}-helix domain of Aap is replaced by tetanus toxin fragment C, we elicit a potent neutralizing antibody response that protects mice against a lethal challenge. A similar strain of S. epidermidis expressing an Aap-SpyCatcher chimera can be conjugated with recombinant immunogens; the resulting labeled commensal elicits high titers of antibody under conditions of physiologic colonization, including a robust IgA response in the nasal mucosa. Thus, immunity to a common skin colonist involves a coordinated T and B cell response, the latter of which can be redirected against pathogens as a novel form of topical vaccination.

microbiology↗

bioRxiv2023

A Virus-like particle-based bivalent PCSK9 vaccine lowers LDL-cholesterol levels in Non-Human Primates

Elevated low-density lipoprotein cholesterol (LDL-C) is an important risk factor in the development of atherosclerotic cardiovascular disease (ASCVD). Inhibitors of proprotein convertase subtilisin/kexin type 9 (PCSK9), a negative regulator of LDL-C metabolism, have emerged as promising approaches for reducing elevated LDL-C levels. Here, we evaluated the cholesterol lowering efficacy of virus-like particle (VLP) based vaccines that target epitopes found within the LDL receptor (LDL-R) binding domain of PCSK9. In both mice and non-human primates, a bivalent VLP vaccine targeting two distinct epitopes on PCSK9 elicited strong and durable antibody responses and lowered cholesterol levels. In macaques, a VLP vaccine targeting a single PCSK9 epitope was only effective at lowering LDL-C levels in combination with statins, whereas immunization with the bivalent vaccine lowered LDL-C without requiring statin co-administration. These data highlight the efficacy of an alternative, vaccine-based approach for lowering LDL-C.

immunology↗

bioRxiv2022

Inducible Bronchus-Associated Lymphoid Tissue in SARS-CoV-2 Infected Rhesus Macaques

Pulmonary immunity against SARS-CoV-2 infection has not been well studied. This study investigated the distribution of immune cells int the lungs of 8 rhesus macaques experimentally infected with SARS-CoV-2, and euthanized 11-14 days later. Using immunohistochemistry, inducible bronchus-associated lymphoid tissue was found in all animals. The inducible bronchus-associated lymphoid tissues were composed of B cells, T cells, and follicular dendritic cells with evidence of lymphocyte priming and differentiation. This suggests local immunity plays an important role in the SARS-CoV-2 infection. Further study of local immunity in the lung would benefit our understanding of SARS-CoV-2 pathogenesis and could lead to new interventions to control the SARS-CoV-2 infection and disease.

pathology↗

bioRxiv2022

Zika virus persistence in the male macaque reproductive tract

Zika virus (ZIKV) is unique among mosquito-borne flaviviruses in that it is also vertically and sexually transmitted by humans. The male reproductive tract is thought to be a ZIKV reservoir; however, the reported magnitude and duration of viral persistence in male genital tissues varies widely in humans and non-human primate models. ZIKV tissue and cellular tropism and potential effects on male fertility also remain unclear. The objective of this study was to resolve these questions by analyzing archived genital tissues from 51 ZIKV-inoculated male macaques and correlating data on plasma viral kinetics, tissue tropism, and ZIKV-induced pathological changes in the reproductive tract. We hypothesized that ZIKV would persist in the male macaque genital tract for longer than there was detectable viremia, where it would localize to germ and epithelial cells and associate with lesions. We detected ZIKV RNA and infectious virus in testis, epididymis, seminal vesicle, and prostate gland. In contrast to prepubertal males, sexually mature macaques were significantly more likely to harbor persistent ZIKV RNA or infectious virus somewhere in the genital tract, with detection as late as 60 days post-inoculation. ZIKV RNA localized primarily to testicular stem cells/sperm precursors and epithelial cells, including Sertoli cells, epididymal duct epithelium, and glandular epithelia of the seminal vesicle and prostate gland. ZIKV infection was associated with microscopic evidence of inflammation in the epididymis and prostate gland of sexually mature males, which could have significant effects on male fertility. The findings from this study increase our understanding of persistent ZIKV infection which can inform risk of sexual transmission during assisted reproductive therapies as well as potential impacts on male fertility. Author SummaryZika virus (ZIKV) spread since 2015 led to establishment of urban epidemic cycles involving humans and Aedes mosquitoes. ZIKV is also sexually and vertically transmitted and causes congenital Zika syndrome. Together, these features show that ZIKV poses significant global public health risks. By virtue of similar reproductive anatomy and physiology to humans, macaques serve as a useful model for ZIKV infection. However, macaque studies to date have been limited by small sample size, typically 1 to 5 animals. Although mounting evidence identifies the male reproductive tract as a significant ZIKV reservoir, data regarding the duration of ZIKV persistence, potential for sexual transmission, and male genitourinary sequelae remain sparse. Here, we analyzed archived genital tissues from more than 50 ZIKV-inoculated male macaques. Our results show that ZIKV can persist in the male macaque reproductive tract after the resolution of viremia, with virus localization to sperm precursors and epithelial cells, and microscopic evidence of inflammation in the epididymis and prostate gland. Additionally, we show that freezing is not a viable method of destroying infectious ZIKV. Our findings help explain cases of sexual transmission of ZIKV in humans, which also carries a risk for transmission via assisted fertility procedures, even after resolution of detectable viremia.

pathology↗

bioRxiv2022

Distinct upper airway epithelium interferon-stimulated and profibrotic gene expression between adult and infant rhesus macaques infected with SARS-CoV-2

The global spread of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) and its associated coronavirus disease (COVID-19) has led to a pandemic of unprecedented scale. An intriguing feature of the infection is the minimal disease in most children, a demographic at higher risk for respiratory viral diseases. To elucidate age-dependent effects of SARS-CoV-2 pathogenesis, we inoculated two rhesus macaque monkey dam-infant pairs with SARS-CoV-2 and conducted virological and transcriptomic analysis of the respiratory tract and evaluated systemic cytokine and antibody responses. Viral RNA levels in all sampled mucosal secretions were comparable across dam-infant pairs in the respiratory tract. Despite comparable viral loads, adult macaques showed higher IL-6 in serum while CXCL10 was induced in all animals. Both groups mounted neutralizing antibody (nAb) responses, with infants showing a more rapid induction at day 7. Transcriptome analysis of tracheal tissue isolated at day 14 post-infection revealed significant upregulation of multiple interferon-stimulated genes in infants compared to adults. In contrast, a profibrotic transcriptomic signature with genes associated with cilia structure and function, extracellular matrix (ECM) composition and metabolism, coagulation, angiogenesis, and hypoxia was induced in adults compared to infants. Our observations suggest age-dependent differential airway responses to SARS-CoV-2 infection that could explain the distinction in pathogenesis between infants and adults.

immunology↗

bioRxiv2021

Vaccine-induced, high magnitude HIV Env-specific antibodies with Fc-mediated effector functions are insufficient to protect infant rhesus macaques against oral SHIV infection

Improved access to antiretroviral therapy and antenatal care have significantly reduced in-utero and peri-partum mother-to-child HIV transmission. However, as breastmilk transmission of HIV still occurs at an unacceptable rate there remains a need to develop an effective vaccine for the pediatric population. Previously, we compared different HIV vaccine strategies, intervals, and adjuvants in infant rhesus macaques to optimize the induction of HIV envelope (Env)-specific antibodies with Fc-mediated effector function. Here, we tested the efficacy of an optimized vaccine regimen against oral SHIV acquisition in infant macaques. One group of 12 animals was immunized with 1086.c gp120 protein adjuvanted with 3M-052 in stable emulsion and Modified Vaccinia Ankara (MVA) virus vector expressing 1086.c HIV Env, while the control group (n=12) was immunized only with empty MVA. The first vaccine dose was given within 10 days of birth and booster doses were administered at weeks 6 and 12. The vaccine regimen induced Env-specific plasma IgG antibodies capable of antibody-dependent cellular cytotoxicity (ADCC) and phagocytosis (ADCP). Beginning at week 15, infants were exposed orally to escalating doses of heterologous SHIV-1157(QNE)Y173H once a week until infected. Despite the induction of strong Fc-mediated antibody responses, the vaccine regimen did not reduce the risk of infection, time to acquisition, or peak viremia compared to controls. Our results suggest that the non-neutralizing Env-specific antibodies with Fc effector function elicited by this vaccine regimen were insufficient for protection against heterologous oral SHIV infection shortly after the final immunization. IMPORTANCEWomen of childbearing age are three times more likely to contract HIV infection than their male counterparts. Poor HIV testing rates coupled with low adherence to antiretroviral therapy (ART) result in a high risk of mother-to-infant HIV transmission, especially during the breastfeeding period. A preventative vaccine could curb pediatric HIV infections, reduce potential health sequalae, and prevent the need for lifelong ART in this population. The results of the current study imply that the HIV Env-specific IgG antibodies elicited by this candidate vaccine regimen, despite high magnitude of Fc-mediated effector function, but lack of neutralizing antibodies and polyfunctional T cell responses, were insufficient to protect infant rhesus macaques against oral virus acquisition.

immunology↗

bioRxiv2021

Early post-infection treatment of SARS-CoV-2 infected macaques with human convalescent plasma with high neutralizing activity reduces lung inflammation

Early in the SARS-CoV-2 pandemic, there was a high level of optimism based on observational studies and small controlled trials that treating hospitalized patients with convalescent plasma from COVID-19 survivors (CCP) would be an important immunotherapy. However, as more data from controlled trials became available, the results became disappointing, with at best moderate evidence of efficacy when CCP with high titers of neutralizing antibodies was used early in infection. To better understand the potential therapeutic efficacy of CCP, and to further validate SARS-CoV-2 infection of macaques as a reliable animal model for testing such strategies, we inoculated 12 adult rhesus macaques with SARS-CoV-2 by intratracheal and intranasal routes. One day later, 8 animals were infused with pooled human CCP with a high titer of neutralizing antibodies (RVPN NT50 value of 3,003), while 4 control animals received normal human plasma. Animals were monitored for 7 days. Animals treated with CCP had detectable levels of antiviral antibodies after infusion. In comparison to the control animals, they had similar levels of virus replication in the upper and lower respiratory tract, but had significantly reduced interstitial pneumonia, as measured by comprehensive lung histology. By highlighting strengths and weaknesses, data of this study can help to further optimize nonhuman primate models to provide proof-of-concept of intervention strategies, and guide the future use of convalescent plasma against SARS-CoV-2 and potentially other newly emerging respiratory viruses. Author summaryThe results of treating SARS-CoV-2 infected hospitalized patients with COVID-19 convalescent plasma (CCP), collected from survivors of natural infection, have been disappointing. The available data from various studies indicate at best moderate clinical benefits only when CCP with high titer of neutralizing antibodies was infused early in infection. The macaque model of SARS-CoV-2 infection can be useful to gain further insights in the value of CCP therapy. In this study, animals were infected with SARS-CoV-2 and the next day, were infused with pooled human convalescent plasma, selected to have a very high titer of neutralizing antibodies. While administration of CCP did not result in a detectable reduction in virus replication in the respiratory tract, it significantly reduced lung inflammation. These data, combined with the results of monoclonal antibody studies, emphasize the need to use products with high titers of neutralizing antibodies, and guide the future development of CCP-based therapies.

immunology↗

bioRxiv2021

Different adjuvanted pediatric HIV envelope vaccines induced distinct plasma antibody responses despite similar B cell receptor repertoires in infant rhesus macaques.

Different HIV vaccine regimens elicit distinct plasma antibody responses in both human and nonhuman primate models. Previous studies in human and non-human primate infants showed that adjuvants influenced the quality of plasma antibody responses induced by pediatric HIV envelope vaccine regimens. We recently reported that use of the 3M052-SE adjuvant and longer intervals between vaccinations are associated with higher magnitude of antibody responses in infant rhesus macaques. However, the impact of different adjuvants in HIV vaccine regimens on the developing infant B cell receptor (BCR) repertoire has not been studied. This study evaluated whether pediatric HIV envelope vaccine regimens with different adjuvants induced distinct antigen-specific memory B cell repertoires and whether specific immunoglobulin (Ig) immunogenetic characteristics are associated with higher magnitude of plasma antibody responses in vaccinated infant rhesus macaques. We utilized archived preclinical pediatric HIV vaccine studies PBMCs and tissue samples from 19 infant rhesus macaques immunized either with (i) HIV Env protein with a squalene adjuvant, (ii) MVA-HIV and Env protein coadministered using a 3-week interval, (iii) MVA-HIV prime/ protein boost with an extended 6-week interval between immunizations, or (iv) with HIV Env administered with 3M-052-SE adjuvant. Frequencies of vaccine-elicited HIV Env-specific memory B cells from PBMCs and tissues were similar across vaccination groups (frequency range of 0.06-1.72%). There was no association between vaccine-elicited antigen-specific memory B cell frequencies and plasma antibody titer or avidity. Moreover, the epitope specificity and Ig immunogenetic features of vaccine-elicited monoclonal antibodies did not differ between the different vaccine regimens. These data suggest that pediatric HIV envelope vaccine candidates with different adjuvants that previously induced higher magnitude and quality of plasma antibody responses in infant rhesus macaques were not driven by distinct antigen-specific memory BCR repertoires.

immunology↗

bioRxiv2021

SARS-CoV-2 Vaccines Elicit Durable Immune Responses in Infant Rhesus Macaques

Early life SARS-CoV-2 vaccination has the potential to provide lifelong protection and achieve herd immunity. To evaluate SARS-CoV-2 infant vaccination, we immunized two groups of 8 infant rhesus macaques (RMs) at weeks 0 and 4 with stabilized prefusion SARS-CoV-2 S-2P spike (S) protein, either encoded by mRNA encapsulated in lipid nanoparticles (mRNA-LNP) or mixed with 3M-052-SE, a TLR7/8 agonist in a squalene emulsion (Protein+3M-052-SE). Neither vaccine induced adverse effects. High magnitude S-binding IgG and neutralizing infectious dose 50 (ID50) >103 were elicited by both vaccines. S-specific T cell responses were dominated by IL-17, IFN-{gamma}, or TNF-. Antibody and cellular responses were stable through week 22. The S-2P mRNA-LNP and Protein-3M-052-SE vaccines are promising pediatric SARS-CoV-2 vaccine candidates to achieve durable protective immunity. One-Sentence SummarySARS-CoV-2 vaccines are well-tolerated and highly immunogenic in infant rhesus macaques

immunology↗

bioRxiv2020

Neuroanatomical abnormalities in a nonhuman primate model of congenital Zika virus infection

Zika virus (ZIKV) infection of pregnant women can cause major congenital neuronal abnormalities. In the present study, we evaluated neuropathological consequences of fetal ZIKV exposure in rhesus macaques, a highly translatable animal model for human neural development. Quantitative neuroanatomical analyses of the nearly full-term brains of fetuses infected with ZIKV at gestational days 50, 64, and 90, and three procedure-matched sham-inoculated controls were carried out. Whole tissue sections across a complete cerebral hemisphere were evaluated using immunohistochemical and neuroanatomical staining techniques to detect virus localization, identify affected cell types and evaluate gross neuroanatomical abnormalities. None of the subjects were microcephalic. Immunohistochemical staining revealed the presence of ZIKV in the frontal lobe, which contained activated microglia and showed increased apoptosis of immature neurons. ZIKV-infected animals exhibited macrostructural changes within the occipital lobe, including a reduction in gyrification as well as a higher proportion of white matter. Finally, the ZIKV-infected subjects had abnormalities throughout the visual pathway, including disorganization within the lateral geniculate nucleus (LGN) and primary visual cortex (V1). Regional differences tracked with the temporal patterns of the developing brain and likely reflect the neural progenitor cell tropism ZIKV exhibits - painting a picture of inflammatory processes related to viral infiltration sweeping through the cortex, followed by a wave of cell death resulting in morphological changes. These findings may help explain why some infants born with normal sized heads during the ZIKV epidemic manifest developmental challenges as they age, and ultimately may contribute to developing effective treatments and interventions. One sentence summaryMacaque fetuses infected with Zika virus show both macro- and micro-scale neuropathological abnormalities, including decreased gyrencephality, relative increases in cortical white matter, activation of glia, and increased apoptosis.

neuroscience↗

bioRxiv2020

Two sides of a coin: a Zika virus mutation selected in pregnant rhesus macaques promotes fetal infection in mice but at a cost of reduced fitness in nonpregnant macaques and diminished transmissibility by vectors

Although fetal death is now understood to be a severe outcome of congenital Zika syndrome, the role of viral genetics is still unclear. We sequenced Zika virus (ZIKV) from a rhesus macaque fetus that died after inoculation and identified a single intra-host mutation, M1404I, in the ZIKV polyprotein, located in NS2B. Targeted sequencing flanking position 1404 in 9 additional macaque mothers and their fetuses identified M1404I at sub-consensus frequency in the majority (5 of 9, 56%) of animals and some of their fetuses. Despite its repeated presence in pregnant macaques, M1404I occurs rarely in humans since 2015. Since the primary ZIKV transmission cycle is human-mosquito-human, mutations in one host must be retained in the alternate host to be perpetuated. We hypothesized that ZIKV I1404 increases fitness in non-pregnant macaques and pregnant mice but is less efficiently transmitted by vectors, explaining its low frequency in humans during outbreaks. By examining competitive fitness relative to M1404, we observed that I1404 produced lower viremias in non-pregnant macaques and was a weaker competitor in tissues. In pregnant wildtype mice ZIKV I1404 increased the magnitude and rate of placental infection and conferred fetal infection, contrasting with M1404, which was not detected in fetuses. Although infection and dissemination rates were not different, Ae. aegypti transmitted ZIKV I1404 more poorly than M1404. Our data highlight the complexity of arbovirus mutation-fitness dynamics, and suggest that intrahost ZIKV mutations capable of augmenting fitness in pregnant vertebrates may not necessarily spread efficiently via mosquitoes during epidemics. IMPORTANCEAlthough Zika virus infection of pregnant women can result in congenital Zika syndrome, the factors that cause the syndrome in some but not all infected mothers are still unclear. We identified a mutation that was present in some ZIKV genomes in experimentally inoculated pregnant rhesus macaques and their fetuses. Although we did not find an association between the presence of the mutation and fetal death, we performed additional studies with it in non-pregnant macaques, pregnant mice, and mosquitoes. We observed that the mutation increased the ability of the virus to infect mouse fetuses but decreased its capacity to produce high levels of virus in the blood of non-pregnant macaques and to be transmitted by mosquitoes. This study shows that mutations in mosquito-borne viruses like ZIKV that increase fitness in pregnant vertebrates may not spread in outbreaks when they compromise transmission via mosquitoes and fitness in non-pregnant hosts.

microbiology↗

bioRxiv2020

Genomic insights into the host specific adaptation of the Pneumocystis genus and emergence of the human pathogen Pneumocystis jirovecii

Pneumocystis jirovecii, the fungal agent of human Pneumocystis pneumonia, is closely related to macaque Pneumocystis. Little is known about other Pneumocystis species in distantly related mammals, none of which are capable of establishing infection in humans. The molecular basis of host specificity in Pneumocystis remains unknown as experiments are limited due to an inability to culture any species in vitro. To explore Pneumocystis evolutionary adaptations, we have sequenced the genomes of species infecting macaques, rabbits, dogs and rats and compared them to available genomes of species infecting humans, mice and rats. Complete whole genome sequence data enables analysis and robust phylogeny, identification of important genetic features of the host adaptation, and estimation of speciation timing relative to the rise of their mammalian hosts. Our data reveals novel insights into the evolution of P. jirovecii, the sole member of the genus able to infect humans.

evolutionary biology↗

bioRxiv2020

A Combination of Two Human Monoclonal Antibodies Limits Fetal Damage by Zika Virus in Macaques

Human infection by Zika virus (ZIKV) during pregnancy can lead to vertical transmission and fetal aberrations, including microcephaly. Prophylactic administration of antibodies can diminish or prevent ZIKV infection in animal models, but whether passive immunization can protect nonhuman primates and their fetuses during pregnancy has not been determined. Z004 and Z021 are neutralizing monoclonal antibodies to domain III of the envelope (EDIII) of ZIKV. Together the two antibodies protect nonpregnant macaques against infection even after Fc modifications to prevent antibody-dependent enhancement in vitro (ADE) and extend their half-lives. Here we report on prophylactic co-administration of the Fc-modified antibodies to pregnant rhesus macaques challenged 3 times with ZIKV during first and second trimester. The two antibodies did not entirely eliminate maternal viremia but limited vertical transmission protecting the fetus from neurologic damage. Thus, maternal passive immunization with two antibodies to EDIII can shield primate fetuses from the harmful effects of ZIKV. Significance statementZika virus (ZIKV) infection during pregnancy can cause fetal abnormalities. Vaccines against ZIKV are under development, but because of potential safety concerns due to disease enhancing antibodies, and the time required by active immunization to induce protective antibodies, there is a need to explore alternative strategies. Recombinant monoclonal antibodies can be modified to prevent enhancement of infection, and thus could be an efficacious and safe alternative to vaccines to confer rapid protection. We show that prophylactic administration of two engineered antibodies, Z004 and Z021, to pregnant macaques partially protects against fetal neurologic damage and limits vertical transmission of ZIKV.

immunology↗