BACKGROUND: Toll-like receptors contribute to the establishment of adaptive immune responses. OBJECTIVE: The reported studies were conducted to examine the effects of the Toll-like receptor (TLR)-7 ligand, resiquimod, on human naive B-cell differentiation. METHODS: Naive human B cells were cultured with resiquimod in the presence or absence of IL-2 and IL-10. Secreted IgM and IgG were measured by ELISA, and IL-6, IL-10, and IFN-alpha were measured by a multiplex protein array. Cell proliferation was assessed by measuring [(3)H]thymidine uptake. mRNA for activation-induced cytidine deaminase and I(gamma 1)-C(mu) circle transcripts was measured by means of RT-PCR. RESULTS: Resiquimod induced the production of IgM and, to a lesser extent, IgG by naive human B cells in association with the secretion of IL-6 and IL-10, and a weak proliferative response. IL-2 and IL-10 synergized with resiquimod in markedly augmenting resiquimod-induced IgM and IgG production and proliferation. Resiquimod also stimulated production of IgG by B cells isolated from the blood of a patient with the X-linked hyper-IgM syndrome, with a greater response when these cells were costimulated with IL-2 and IL-10. The stimulated naive B cells from healthy volunteers displayed molecular evidence of immunoglobulin class-switch recombination-namely the appearance of activation-induced cytidine deaminase and I(gamma 1)-C(mu) circle transcripts. CONCLUSION: Perturbation of TLR-7 on naive human B cells can lead to the induction of immunoglobulin class switch and IgG production in the absence of B-cell receptor cross-linking and CD40-CD40L interaction. The results are relevant to vaccine development and mechanisms by which microbial infection may lead to autoimmunity.
BACKGROUND: Toll-like receptors contribute to the establishment of adaptive immune responses. OBJECTIVE: The reported studies were conducted to examine the effects of the Toll-like receptor (TLR)-7 ligand, resiquimod, on human naive B-cell differentiation. METHODS: Naive human B cells were cultured with resiquimod in the presence or absence of IL-2 and IL-10. Secreted IgM and IgG were measured by ELISA, and IL-6, IL-10, and IFN-alpha were measured by a multiplex protein array. Cell proliferation was assessed by measuring [(3)H]thymidine uptake. mRNA for activation-induced cytidine deaminase and I(gamma 1)-C(mu) circle transcripts was measured by means of RT-PCR. RESULTS: Resiquimod induced the production of IgM and, to a lesser extent, IgG by naive human B cells in association with the secretion of IL-6 and IL-10, and a weak proliferative response. IL-2 and IL-10 synergized with resiquimod in markedly augmenting resiquimod-induced IgM and IgG production and proliferation. Resiquimod also stimulated production of IgG by B cells isolated from the blood of a patient with the X-linked hyper-IgM syndrome, with a greater response when these cells were costimulated with IL-2 and IL-10. The stimulated naive B cells from healthy volunteers displayed molecular evidence of immunoglobulin class-switch recombination-namely the appearance of activation-induced cytidine deaminase and I(gamma 1)-C(mu) circle transcripts. CONCLUSION: Perturbation of TLR-7 on naive human B cells can lead to the induction of immunoglobulin class switch and IgG production in the absence of B-cell receptor cross-linking and CD40-CD40L interaction. The results are relevant to vaccine development and mechanisms by which microbial infection may lead to autoimmunity.
Authors: Victoria Jeisy-Scott; Jin Hyang Kim; William G Davis; Weiping Cao; Jacqueline M Katz; Suryaprakash Sambhara Journal: J Virol Date: 2012-07-25 Impact factor: 5.103