The Role of Idiotypic Interactions and B-cell Subsets in Development of the B-cell Repertoire

In the present study, a modification of the splenic focus system is used to analyze the S. typhimurium strain TML (TML)-specific B cell repertoire. The results show that the frequency of primary TML-specific splenic B cells in CBA/Ca mice is approximately 1 per 10(5) B cells and less than 30% of these B cells are specific for LPS. In contrast, the frequency of memory TML-specific cells is approximately 1 per 5-8 X 10(3) splenic B cells and greater than 95% of these B cells are specific for LPS. These results suggest that the frequency of primary TML-specific B cells is extremely low and that it expands 15-20-fold after antigen exposure. It is interesting that less than 30% of the primary B cells are specific for the LPS molecule since it is considered to be the major antigenic determinant on Salmonella organisms. Furthermore, the majority of the LPS-specific anti-TML antibody-producing clones are directed against the LPS O antigen region. Conversely, more than half to two-thirds of the memory LPS-specific anti-TML B cell clones are directed against the KDO or lipid A region of the LPS molecule. These results indicate that the preferential expansion of LPS-specific B cell clones observed after immunization resides primarily in the B cell subsets responsive to the KDO/lipid A moieties on the LPS molecule. Finally, unlike B cell responses to chemically defined antigens, TML stimulates very little IgG1 antibody. IgG2 and IgA isotypes appear to play a predominant role in anti-TML antibody responses, although all H chain classes are produced to some extent. Collectively, these findings are consistent with the responses reported for two other natural antigens, HA and PC. Hence, the pattern of stimulation by infectious agents, such as S. typhimurium, appears to be distinct from that of synthetic antigens. Thus, the studies presented herein have begun to provide insights into those subsets of B cells responsive to S. typhimurium and other infectious disease organisms.

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The role of notch signaling in the development of a normal B‐cell repertoire

Immunology and Cell Biology ◽

10.1038/icb.2009.73 ◽

2009 ◽

Vol 88 (2) ◽

pp. 117-124 ◽

Cited By ~ 17

Author(s):

Mark N Cruickshank ◽

Daniela Ulgiati

Keyword(s):

B Cell ◽

Notch Signaling ◽

Cell Repertoire ◽

B Cell Repertoire

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Low Numbers of CD27- IgD- 'Double Negative' Senescent B-Cells Early after Reduced Intensity T Cell Depleted Haematopoietic Stem Cell Transplantation Are Predictive of Subsequent Chronic GvHD

Blood ◽

10.1182/blood-2019-131130 ◽

2019 ◽

Vol 134 (Supplement_1) ◽

pp. 4529-4529

Author(s):

Francesca Kinsella ◽

Harriet Protheroe ◽

Hayden Pearce ◽

Charlotte F Inman ◽

Suzy A Eldershaw ◽

...

Keyword(s):

B Cells ◽

B Cell ◽

Chronic Gvhd ◽

Subsequent Development ◽

Haematopoietic Stem Cell ◽

Cell Repertoire ◽

Graft Versus Host ◽

Post Transplant ◽

B Cell Repertoire ◽

B Cell Subsets

Chronic graft versus host disease (cGvHD) is an important complication of allogeneic haematopoietic stem cell transplantation (allo-HSCT). It is now believed that B cells play a major role in the development of cGvHD as evidenced by the efficacy of B-cell directed therapies, and the disturbances in B cell subsets found in patients. This is characterised by a relative lack of naive B cells and increase in CD27+ (antigen experienced) mature B cells that can mediate host directed responses. Despite this the cellular mechanisms underlying the pathogenesis of cGvHD remain unclear. We investigated the phenotype and function of CD19+ B-cell subsets in a cohort of 46 patients undergoing reduced intensity-conditioned allo-HSCT with alemtuzumab. 76% of patients had myeloid disease and 24% lymphoid disease. All patients received PBMC grafts, fludarabine and melphalan conditioning and 10mg/day alemtuzumab from day -5 for 5 days. Overall survival at 3 years was 65% and relapse free survival was 62%. 16% patients experienced acute GvHD (grade 2+) and 29% developed chronic GvHD. B cell subsets were examined at 6 weeks post-transplant and CD27-IgD- 'double negative' (DN) B-cells were seen to dominate the B cell repertoire (mean 55% of B-cells). DN B-cells are an ill-defined memory B cell subset associated with immune senescence, auto-immune inflammatory conditions and cancer but their role in allo-HSCT has not been described. The frequency of DN B-cells decreased over time, as the naive B cell compartment regenerated, but still represented 31% of B cells at 1 year. However the mean number of DN B cells remained remarkably stable (0.033x109/L at 6 weeks v 0.037x109/L at 1 year). 14% of DN B-cells early post-transplant were transitional (CD24high CD38high) whilst 10% were plasma cells (CD24- CD38high). The remaining 76% had increased CD86 expression compared to memory B-cells (16% v 9.6%; *p=0.039) and lower levels of surface immunoglobulin. DN B-cells were less functional than other B cell subsets with decreased proportions of cells producing IL-2 (20%), IL-6 (17%), IFN-γ (6.2%), and IL-10 (6.2%) compared to naive or memory B cells. They also demonstrated reduced proliferation to in vitro stimulation (Ki-67 5.3%). Importantly, the proportion of DN B cells early post transplant was then studied in relation to transplant outcome and a lower frequency of cells was found to be correlated with subsequent development of cGvHD (38% v 62%; *p=0.04). These data show that senescent CD27-IgD- DN B-cells dominate the B cell repertoire in the early period after lymphocyte-depleted allo-HSCT. Furthermore, they are significantly reduced in patients who subsequently develop cGvHD. These data suggest that early B cell senescence can directly regulate the subsequent development of chronic graft versus host disease and indicate that the composition of the B cell repertoire at an early time-point post-transplant may be used to predict subsequent clinical outcome. Disclosures No relevant conflicts of interest to declare.

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Role of Receptor Revision in Forming a B Cell Repertoire

Clinical Immunology ◽

10.1006/clim.2002.5290 ◽

2002 ◽

Vol 105 (1) ◽

pp. 1-8 ◽

Cited By ~ 9

Author(s):

Jane Seagal ◽

Doron Melamed

Keyword(s):

B Cell ◽

Cell Repertoire ◽

B Cell Repertoire

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B-cell repertoire formation: role of the recombination signal sequence in non-random V segment utilization

Immunological Reviews ◽

10.1111/j.1600-065x.2000.imr017508.x ◽

2000 ◽

Vol 175 (1) ◽

pp. 59-69 ◽

Cited By ~ 34

Author(s):

Ann J. Feeney ◽

Alan Tang ◽

Kisani M. Ogwaro

Keyword(s):

B Cell ◽

Signal Sequence ◽

Recombination Signal Sequence ◽

Cell Repertoire ◽

Recombination Signal ◽

B Cell Repertoire

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AB0146 DRUG DEPENDENT ALTERATIONS IN B-CELL REPERTOIRE IN SYSTEMIC LUPUS ERYTHEMATOSUS PATIENTS WITH LOW DISEASE ACTIVITY

Annals of the Rheumatic Diseases ◽

10.1136/annrheumdis-2020-eular.4412 ◽

2020 ◽

Vol 79 (Suppl 1) ◽

pp. 1373.2-1373

Author(s):

S. Zenz ◽

B. Dreo ◽

B. Prietl ◽

S. Kofler ◽

H. Sourij ◽

...

Keyword(s):

B Cells ◽

Disease Activity ◽

B Cell ◽

Lupus Erythematosus ◽

Cell Repertoire ◽

Low Disease Activity ◽

B Cell Repertoire ◽

Drug Dependent ◽

B Cell Subsets

Background:B-cells play a major role in the pathogenesis and perpetuation of the immune response in systemic lupus erythematosus (SLE). So far, B-cell subtypes have been studied well, but the precise mechanisms of the B-cell alterations during disease activity and during remission, depending on different medication, are still unclear.Objectives:The aim of our study was to investigate the drug dependent alterations in the B-cell repertoire of SLE patients with low disease activity (SLEDAI – 2K ≤4).Methods:Peripheral blood samples from 39 patients suffering from SLE (mean±SD; age 43±13 years, 87.2% females, disease duration 11.1±7 years) were drawn over 2 years. All SLE patients were in remission or low disease activity (median±SE, SLEDAI of 2.0±1.5). B-cells were characterized using CD19, CD20, CD5, CD27 antibodies and were grouped in naïve (IgD+27-), non-switched memory (IgD+, CD27+), memory (IgD-,CD27+), B1 (CD5+27-) and MBL-like (CD5++) B-cells. A quantitative flow cytometric bead-based assay (QuantiBRITE PE kit from Becton Dickinson) was used for the estimation of CD19 antibodies bound per cell. Further, CD38 and CD86 antibodies were used to characterize the B-cell subsets. All cytometric measurements were performed using a standardized BD LSR Fortessa platform. After 3 years of follow-up, patients’ data about disease activity and current medication were obtained.Results:22 SLE patients were treated with hydroxychloroquine (85.8%) and 19 patients received mycophenolate mofetil (MMF; n=14; 54.6%) or azathioprine (AZA; n= 5; 19.5 %). 5 patients were treated with other DMARDs. Independently of hydroxychloroquine and/or MMF, no significant differences were seen in naïve, non-switched memory, post-switched memory, plasma blasts, B1- or MBL-like B-cells. Patients treated with AZA had significantly lower naïve B-cells (mean±SD, 39.3±6.7vs. 73.1±19.3 %; p = 0.028), but had significantly higher IgD-post switched B-cells (31.2±9.1 vs.12.5 ±9.2 %; p = 0.028, respectively) compared with no AZA-treatment. Interestingly, activated B-cells (5.5±1.5 vs. 1.8±1.1%; p = 0.009) were significantly higher in AZA-treated. After 3 years of follow-up, almost all patients were in remission (median±SE, SLEDAI of 2.0±2.0), except of 3 patients with a SLEDAI of ≥ 6. Interestingly, those patients had at baseline, statistically higher naïve B-cells (p = 0.041) and lower B1-like B-cells (p =0.020) compared with patients with low disease activity.Conclusion:Our results suggest that independently of hydroxychloroquine and/or MMF treatment, all patients with low disease activity had similar normal B-cell subsets. Interestingly, in the small group of patients who were treated with AZA, a reduced regeneration of B-cells was shown. Patients with higher disease and high naïve B-cells showed an increased disease activity after three years.Acknowledgments:The research was performed in “CBmed” and funded by the Austrian Federal Government within the COMET K1 Centre Program, Land Steiermark and Land Wien.Disclosure of Interests:None declared

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