Topic
Memory B-Lymphocyte
About: Memory B-Lymphocyte is a research topic. Over the lifetime, 6 publications have been published within this topic receiving 106 citations.
Papers
TL;DR: The results suggest that the CD40 signaling pathway is instrumental for the clonal expansion of the memory B cell pool, but does not operate in the later phase of the response, which allows their maturation into antibody‐secreting cells.
Abstract: It is generally accepted that memory B cells can be defined by their ability to produce, upon antigenic challenge, somatically mutated antibody molecules characterized by an increased affinity and by the expression of a downstream heavy chain isotype. However, the inability to isolate this particular B cell compartment has precluded the study of memory B lymphocyte physiology in man. We previously reported on the identification of an IgD- B cell subset in human tonsils that we defined as CD38- B cells, whose phenotype is highly reminiscent of that of memory B lymphocytes from the splenic marginal zone of rodents. In the present study, we developed a model of the measles virus (MV)-specific secondary antibody response in vitro to assess the presence of memory B lymphocytes in different B cell subsets isolated from human tonsils and explore the activation requirements of human memory B cells. Our findings show that the memory B cell pool resides in the CD38- B cell subpopulation and that the differentiation of MV-activated memory B cells into antibody-secreting cells can be achieved upon co-stimulation with interleukin (IL)-2 and IL-10, but does not require engagement of CD40. Interestingly, the CD40-mediated signal was found to synergize with Ig-cross-linking agents for the proliferation of memory B cells, but strongly suppressed their capacity to differentiate along the plasmacytoid pathway. Collectively, our results suggest that the CD40 signaling pathway is instrumental for the clonal expansion of the memory B cell pool, but does not operate in the later phase of the response, which allows their maturation into antibody-secreting cells.
60 citations
TL;DR: It is demonstrated that short-term EBV persistence can occur in the absence of a germinal center reaction and a classical memory B-cell population.
Abstract: Epstein-Barr virus (EBV) is a ubiquitous human herpesvirus that persists in the body for life after primary infection. The primary site of EBV persistence is the memory B lymphocyte, but whether the virus initially infects naive or memory B cells is still disputed. We have analyzed EBV infection in nine cases of X-linked hyper-immunoglobulin M (hyper-IgM) syndrome who, due to a mutation in CD40 ligand gene, do not have a classical, class-switched memory B-cell population (IgD(-) CD27(+)). We found evidence of EBV infection in 67% of cases, which is similar to the infection rate found in the general United Kingdom population (60 to 70% for the relevant age range). We detected EBV DNA in peripheral blood B cells and showed in one case that the infection was restricted to the small population of nonclassical, germinal center-independent memory B cells (IgD(+) CD27(+)). Detection of EBV small RNAs, latent membrane protein 2, and EBV nuclear antigen 3C expression in peripheral blood suggests full latent viral gene expression in this population. Analysis of EBV DNA in serial samples showed variability over time, suggesting cycles of infection and loss. Our results demonstrate that short-term EBV persistence can occur in the absence of a germinal center reaction and a classical memory B-cell population.
25 citations
Journal Article•
TL;DR: In addition to the expansion of the memory B cell population, the model observed the development of 2 immunoregulatory cycles previously observed only in vivo, and in the presence of persistent antigen, a cyclical PFC response was seen.
Abstract: An in vitro model for the propagation and expansion of the memory B lymphocyte population is described. DNP-BGG immune cells were mixed with OVA immune cells and challenged immediately with DNP-OVA. After the 1st response had begun to wane, the cells were rechallenged with DNP-OVA (day 11 of culture). An average of 13-fold more PFC were observed after delayed challenge (day 11). This expansion in the PFC response was an antigen-dependent process and did not involve recruitment of new memory cells from the virgin lymphocyte pool. The level of expansion of the memory cell pool was also calculated using limiting dilution analysis and was found to fall in a range of 16- to 67-fold increase in precursor frequency. In addition to the expansion of the memory B cell population, we also observed the development of 2 immunoregulatory cycles previously observed only in vivo. First, in the presence of persistent antigen, a cyclical PFC response was seen. Second, after day 10 of culture, optimal PFC numbers were observed only when DNP-lysine was added to the plaque assay. Such hapten-augmentable PFC responses have been reported by other investigators as indicative of anti-idiotypic regulation. This possibility is examined more extensively in the following communication.
13 citations
Journal Article•
TL;DR: The data suggest Con A Sup may augment the TI responses to DNP-dextran and TNP-T4 by recruiting additional precursors from a memory cell pool formerly insensitive to these forms of antigen.
Abstract: Spleen cells from mice primed to trinitrophenyl-keyhole limpet hemocyanin (TNP-KLH) generate IgG anti-TNP memory responses when stimulated in vitro with either thymus-dependent (TD) or thymus-independent (TI) forms of the hapten. When supernatants from Con A-stimulated spleen cells (Con A Sup) were added to such secondary cultures the TI responses to DNP-dextran or TNP-T4 were augmented; the TD response to TNP-KLH was suppressed. Passage over Sephadex and addition of alpha-methyl-D-mannoside did not inhibit augmentation by Con A Sup, indicating that augmentation did not result from direct action of the lectin on the responding cells. Augmentation occurred equally well in cultures that had been depleted of T cells by treatment with anti-Thy-1.2 and complement. Limiting dilution analyses revealed that Con A Sup increased the frequency of TI-responding precursors approximately threefold while causing a concomitant decrease in TD-responding precursors. To determine the relationship of the additional TI precursors and those normally detected in the absence of Con A Sup, the TI-responding IgG precursors were first eliminated through selective suicide by using DNP-dextran plus BUdR and light treatment; subsequently no TI-responding IgG PFC could be detected to DNP-dextran unless Con A Sup was also added. The data suggest Con A Sup may augment the TI responses to DNP-dextran and TNP-T4 by recruiting additional precursors from a memory cell pool formerly insensitive to these forms of antigen.
10 citations
TL;DR: In this paper, the authors analyzed the immunological memory to SARS-CoV-2 in 102 recovered patients aged over 60 years several months after the infection had been resolved.
Abstract: Understanding how older people respond to SARS-CoV-2 is critical if we are to confront the COVID-19 pandemic and establish effective vaccination strategies. Immunosenescence reduces the ability to respond to neoantigens and may compromise the life of infected individuals. Here, we analysed the immunological memory to SARS-CoV-2 in 102 recovered patients aged over 60 years several months after the infection had been resolved. Specific memory T lymphocytes against the virus were measured by IFN-γ and granzyme B release by ELISpot; memory B lymphocyte responses were quantified by detection of anti-S IgG1 producer cells by ELISpot and anti-S and anti-N antibodies were determined by ELISA. Memory T lymphocytes were found in peripheral blood of most of the studied donors, more than seven months after the infection in some of them. Fewer patients maintained memory B lymphocytes, but antibodies, mainly anti-S, were highly durable and positively correlated with T responses. More robust humoral responses were found in patients who had more severe symptoms and had been admitted to hospital. We concluded that specific immunity against SARS-CoV-2 is effectively preserved regardless of age, despite the great heterogeneity of their immune responses, and that memory T lymphocytes and anti-S IgG might be more durable than memory B cells and anti-N IgG.
7 citations
Related Topics (5)
Performance Metrics
| Year | Papers |
|---|---|
| 2021 | 1 |
| 2014 | 1 |
| 2005 | 1 |
| 1996 | 1 |
| 1982 | 1 |
| 1981 | 1 |