Biology subjects

Paschall, A. V.

Publications and source records attributed to Paschall, A. V..

3 recordsLinked to original sources

bioRxiv2024

A regulatory B cell subpopulation expressing CD301b lectin promotes breast cancer growth

Aberrant tumor glycosylation can alter immune recognition; however, the specific influence of glycan-lectin interactions on tumor progression remains poorly understood. Here, we identify the C-type lectin receptor CD301b (encoded by Mgl2) as a regulator of immune activity within the breast tumor microenvironment (TME). Using a murine triple-negative breast cancer model, we demonstrate that tumors expressing the Tn glycoantigen grow more rapidly, and this growth is facilitated by CD301b immune cells. Depletion or genetic loss of CD301b markedly suppressed tumor growth, indicating that CD301b promotes tumor progression through myeloid-tumor interactions. Phenotypic analyses revealed that CD301b cells within tumors are type 2 conventional dendritic cells (cDC2s), a subset known to influence immune polarization. Single-cell RNA sequencing of human breast cancers showed that the human ortholog CLEC10A is expressed in cDC2-like dendritic cells and select macrophage subsets, suggesting a conserved role for CD301 myeloid populations. Transcriptomic profiling of tumors developed in Mgl2-deficient mice revealed a shift toward an inflammatory, immune-activated state consistent with enhanced antitumor immunity. Together, these findings establish a link between tumor glycosylation and lectin signaling of myeloid cells, highlighting CD301b as a potential target for reprogramming the tumor immune microenvironment in breast cancer.

immunology↗

bioRxiv2021

Modulation of immunosuppressant drug treatment to improve SARS-CoV-2 vaccine efficacy in mice

The COVID-19 pandemic dramatically demonstrated the need for improved vaccination strategies and therapeutic responses to combat infectious diseases. However, the efficacy of vaccines has not yet been demonstrated in combination with commonly used immunosuppressive drug regimens. We sought to determine how common pharmaceutical drugs used in autoimmune disorders can alter immune responses to the SARS-CoV-2 spike protein vaccination. We treated mice with five immunosuppressant drugs (cyclophosphamide, leflunomide, methotrexate, methylprednisolone, and mycophenolate mofetil), each with various mechanisms of action prior to and following immunization with SARS-CoV-2 spike protein. We assessed the functionality of antibody responses to spike protein and compared immune cell populations in mice that received no treatment with those that received continuous or temporarily suspended immune suppressive therapy. All tested immunosuppressants significantly reduced the antibody titers in serum and functional antibody response against SARS-CoV-2 spike protein in immunized mice. Temporarily halting selected immunosuppressants (methylprednisolone and methotrexate, but not cyclophosphamide) improved antibody responses significantly. Through proof-of-principle experiments utilizing a mouse model, we demonstrated that immune suppression in autoimmune disorders through pharmaceutical treatments may impair vaccine response to SARS-CoV-2, and temporary suspension of immunosuppressant treatment may be necessary to mount an effective antibody vaccine response. This work provides feasibility for future clinical assessment of the impact of immunosuppressants on vaccine efficacy in humans. Significance StatementImmunosuppressant regimens are widely used as therapies for a variety of diseases, including autoimmune, inflammatory, and cancer. However, immunosuppressants can impair critical immune responses to vaccination. The impact of standard immunosuppressant use on the critical, developing SARS-CoV-2 vaccination strategies has not been well-described. In this study, we use a mouse model to determine how different immunosuppressant drugs that act through different mechanisms can impair the antibody response to SARS-CoV-2 spike protein, and how modulating these drug regimens may restore antibody levels and function.

immunology↗

bioRxiv2021

Broadly reactive human monoclonal antibodies targeting the pneumococcal histidine triad protein protect against fatal pneumococcal infection

Streptococcus pneumoniae remains a leading cause of bacterial pneumonia despite the widespread use of vaccines. While vaccines are effective at reducing the incidence of most vaccine-included serotypes, a rise in infection due to non-vaccine serotypes, and moderate efficacy against some vaccine included serotypes have contributed to high disease incidence. Additionally, numerous isolates of S. pneumoniae are antibiotic or multi-drug resistant. Several conserved pneumococcal proteins prevalent in the majority of serotypes have been examined as vaccines in preclinical and clinical trials. An additional, yet unexplored tool for disease prevention and treatment is the use of human monoclonal antibodies (mAbs) targeting conserved pneumococcal proteins. Here, we isolate the first human mAbs (PhtD3, PhtD6, PhtD7, PhtD8, PspA16) against the pneumococcal histidine triad protein (PhtD), and the pneumococcal surface protein A (PspA), two conserved and protective antigens. mAbs to PhtD target diverse epitopes on PhtD, and mAb PspA16 targets the N-terminal segment of PspA. The PhtD-specific mAbs bind to multiple serotypes, while mAb PspA16 serotype breadth is limited. mAbs PhtD3 and PhtD8 prolong the survival of mice infected with pneumococcal serotype 3. Furthermore, mAb PhtD3 prolongs the survival of mice in intranasal and intravenous infection models with pneumococcal serotype 4, and in mice infected with pneumococcal serotype 3 when administered 24 hours after pneumococcal infection. All PhtD and PspA mAbs demonstrate opsonophagocytic activity, suggesting a potential mechanism of protection. Our results provide new human mAbs for pneumococcal disease prevention and treatment, and identify epitopes on PhtD and PspA recognized by human B cells.

immunology↗