Shokrgozar MA, Sam MR, Amirkhani A, Shokri F. Frequency Analysis of HBsAg-specific B Lymphocytes in High-responder Individuals to Recombinant Hepatitis B Vaccine: Comparison of LDA and ELISPOT Assays.
Scand J Immunol 2006;
64:536-43. [PMID:
17032247 DOI:
10.1111/j.1365-3083.2006.01838.x]
[Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The determination of the frequency of antigen-specific lymphocytes may provide invaluable information for the evaluation of the immune response to different antigens and pathogens. Different methods are employed to determine the frequency of specific B lymphocytes in peripheral blood. In this study, the frequency of hepatitis B surface antigen (HBsAg)-specific B lymphocytes was determined by a limiting dilution assay (LDA) and an enzyme-linked immunospot assay (ELISPOT) in seven healthy adult high responders to recombinant HBsAg. Peripheral blood mononuclear cells isolated at different time intervals (1, 2, 4, 8 and 16 weeks) following administration of a booster dose were either transformed with Epstein-Barr virus (LDA) or stimulated with Pokeweed mitogen (ELISPOT). In an LDA, anti-HBs positive wells were screened by a sandwich ELISA and the frequency of specific B lymphocytes was estimated based on the Poisson statistical analysis. In an ELISPOT, coloured spots representing specific B lymphocytes were finally enumerated by stereomicroscope. Our results showed a significant increase in the number of specific B lymphocytes in the first week by an ELISPOT compared with an LDA (1:190 versus 1:13,462) (P < 0.001). No significant differences were observed at other time intervals. A significant correlation was observed between the serum titer of anti-HBs antibody and frequency of HBsAg-specific B cells obtained by LDA and ELISPOT methods at different time intervals. The highest correlation was found at fourth week in LDA (r = 0.83, P < 0.01) and ELISPOT (r = 0.85, P < 0.01) assays. Furthermore, a significant correlation was observed between an LDA and ELISPOT at different time intervals (highest correlation in second week, r = 0.88, P < 0.008). These findings suggest that in addition to technical advantages, such as speed and simplicity, an ELISPOT is a more sensitive assay, compared with an LDA.
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