Antigen-Specific B-Cell Responses to Porcine Reproductive and Respiratory Syndrome Virus Infection

ABSTRACT Porcine reproductive and respiratory syndrome virus (PRRSV) causes an acute, viremic infection of 4 to 6 weeks, followed by a persistent infection lasting for several months. We characterized antibody and B-cell responses to viral proteins in acute and persistent infection to better understand the immunological basis of the prolonged infection. The humoral immune response to PRRSV was robust overall and varied among individual viral proteins, with the important exception of a delayed and relatively weak response to envelope glycoprotein 5 (GP5). Memory B cells were in secondary lymphoid organs, not in bone marrow or Peyer's patches, in contrast to the case for many mammalian species. Potent anti-PRRSV memory responses were elicited to recall antigen in vitro, even though a second infection did not increase the B-cell response in vivo, suggesting that productive reinfection does not occur in vivo. Antibody titers to several viral proteins decline over time, even though abundant antigen is known to be present in lymphoid tissues, possibly indicating ineffective antigen presentation. The appearance of antibodies to GP5 is delayed relative to the resolution of viremia, suggesting that anti-GP5 antibodies are not crucial for resolving viremia. Lastly, viral infection had no immunosuppressive effect on the humoral response to a second, unrelated antigen. Taking these data together, the active effector and memory B-cell responses to PRRSV are robust, and over time the humoral immune response to PRRSV is effective. However, the delayed response against GP5 early in infection may contribute to the prolonged acute infection and the establishment of persistence.

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Humoral Immune Response after the Third SARS-CoV-2 mRNA Vaccination in CD20 Depleted People with Multiple Sclerosis

Vaccines ◽

10.3390/vaccines9121470 ◽

2021 ◽

Vol 9 (12) ◽

pp. 1470

Author(s):

Lutz Achtnichts ◽

Barbara Jakopp ◽

Michael Oberle ◽

Krassen Nedeltchev ◽

Christoph Andreas Fux ◽

...

Keyword(s):

Immune Response ◽

B Cell ◽

Humoral Immune Response ◽

Receptor Binding Domain ◽

Igg Antibodies ◽

Humoral Immune ◽

Cell Responses ◽

The Third ◽

Cell Counts ◽

Anti Cd20

CD20 depletion is a risk factor for unfavorable outcomes of COVID-19 in people with MS (pwMS). Evidence suggests that protective IgG response to mRNA-based vaccines in B cell-depleted individuals is limited. We studied the seroconversion after the third mRNA SARS-CoV-2 vaccine in B cell-depleted pwMS with limited or no IgG response after the standard immunization. Sixteen pwMS treated with ocrelizumab or rituximab received a third homologous SARS-CoV-2 mRNA vaccine, either the Moderna mRNA-1273 or Pfizer-BioNTech’s BNT162b2 vaccine. We quantified the response of IgG antibodies against the spike receptor-binding domain of SARS-CoV-2 four weeks later. An antibody titer of 100 AU/mL or more was considered clinically relevant. The median time between the last infusion of the anti-CD20 treatment and the third vaccination was 22.9 weeks (range 15.1–31.3). After the third vaccination, one out of 16 patients showed an IgG titer deemed clinically relevant. Only the seroconverted patient had measurable B-cell counts at the time of the third vaccination. The development of a humoral immune response remains rare in pwMS on anti-CD20 therapy, even after third dose of the homologous SARS-CoV-2 mRNA vaccine. It remains to be determined whether T-cell responses can compensate for the lack of seroconversion and provide sufficient protection against CoV-2 infections.

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Double immunocytochemical staining for in vivo detection of epitope specificity and isotype of antibody-forming cells against synthetic peptides homologous to human immunodeficiency virus-1.

Journal of Histochemistry & Cytochemistry ◽

10.1177/38.4.1690764 ◽

1990 ◽

Vol 38 (4) ◽

pp. 457-462 ◽

Cited By ~ 9

Author(s):

J D Laman ◽

K Gerritse ◽

M Fasbender ◽

W J Boersma ◽

N van Rooijen ◽

...

Keyword(s):

Immune Response ◽

Lymph Node ◽

B Cell ◽

Immune Complexes ◽

Humoral Immune Response ◽

Synthetic Peptides ◽

Humoral Immune ◽

Epitope Specificity ◽

Hiv 1

Many infections evoke a strong humoral immune response. Some (e.g., HIV-1, EBV, CMV) also lead to disorders of the B-cell system. Data concerning cell dysfunction are largely derived from in vitro studies, which necessarily exclude all microenvironmental influences. The aim of this study was to develop a tool for the investigation of epitope specific humoral immune responses in vivo. Mice were immunized with one of two synthetic peptides, both 21 amino acids long and homologous to regions of the HIV-1 gp160. Cryostat sections of spleen and lymph nodes were incubated with the corresponding peptide coupled to alkaline phosphatase and simultaneously incubated with peroxidase-conjugated rabbit antisera specific for mouse immunoglobulin isotypes. We were able to show simultaneous detection of epitope specificity, isotype, and localization of antibody-forming cells and immune complexes in tissue sections. It should prove useful for in vivo investigation of the development of specific (e.g., anti-HIV-1) humoral immune response, the determination of B-cell specificity in lymph node infiltrates, and the role of immune complexes in lymph node pathology.

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Humoral and cellular immune responses to SARS CoV-2 vaccination in Persons with Multiple Sclerosis and NMOSD patients receiving immunomodulatory treatments

10.1101/2021.12.22.21268127 ◽

2021 ◽

Author(s):

Henry Bock ◽

Thomas Juretzek ◽

Robert Handreka ◽

Johanna Ruhnau ◽

Karl Reuner ◽

...

Keyword(s):

Multiple Sclerosis ◽

Immune Response ◽

T Cell ◽

Immune Responses ◽

B Cell ◽

Humoral Immune Response ◽

Humoral Immune ◽

Cell Responses ◽

Cellular Immune Responses ◽

Cellular Immune

Abstract Background: Vaccination against SARS CoV-2 results in excellent personal protection against a severe course of COVID19. In persons with Multiple Sclerosis (PwMS) vaccination efficacy may be reduced by immunomodulatory medications. Objective: To assess the vaccination induced cellular and humoral immune response in PwMS receiving disease modifiying therapies. Methods: In a monocentric observational study on PwMS and patients with Neuromyelitis optica we quantified the cellular and humoral immune responses to SARS CoV-2. Results: PwMS receiving Glatirameracetate, Interferon-beta, Dimethylfumarate, Cladribine or Natalalizumab had intact humoral and cellular immune responses following vaccination against SARS CoV-2. B-cell depleting therapies reduced B-cell responses but did not affect T cell responses. S1P inhibitors strongly reduced humoral and cellular immune responses. There was a good agreement between the Interferon gamma release assay and the T-SPOT assay used to measure viral antigen induced T-cell responses. Conclusion: This study demonstrates that S1P inhibitors impair the cellular and humoral immune response in SARS CoV-2 vaccination, whereas patients receiving B-cell depleting therapies mount an intact cellular immune response. These data can support clinicians in counselling their PwMS and NMOSD patients during the COVID 19 pandemic.

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