Lapham C, Golding B, Inman J, Blackburn R, Manischewitz J, Highet P, Golding H
Laboratory of Retrovirus Research, Division of Viral Products, Center for Biologics Evaluation and Research, U.S. Food and Drug Administration, Bethesda, Maryland 20892, USA.
J Virol. 1996 May;70(5):3084-92. doi: 10.1128/JVI.70.5.3084-3092.1996.
We have previously shown that immunization of mice with human immunodeficiency virus (HIV)-derived proteins or peptides conjugated to inactivated Brucella abortus induces the secretion of virus-neutralizing antibodies, predominantly of the immunoglobulin G2a (IgG2a) isotype. In addition, B. abortus activates human CD4+ and CD8+ cells to secrete gamma interferon. Since these are both characteristics of a Th1-type immune response, which is associated with the development of cell-mediated immunity, it was important to determine if B. abortus conjugates would also act as a carrier to induce a cytotoxic T-lymphocyte (CTL) response. To test this hypothesis, we conjugated an 18-amino-acid peptide from the V3 loop of the MN strain of HIV-1 gp120 that contains both B- and cytotoxic T-cell epitopes to B. abortus (B. abortus-MN 18-mer). A 10-amino-acid fragment of this peptide has been shown to be the minimal CTL determinant presented by murine H-2Dd. It was found that two in vivo immunizations with 10(8) organisms of B. abortus-MN 18-mer followed by in vitro stimulation with peptide induced a virus-specific CTL response. Conjugation to B. abortus was required for in vivo priming, since there was no induction of memory CTLs when B. abortus was only mixed with peptide. Targets pulsed with peptide as well as those infected with a vaccinia virus encoding HIV gp160 were killed, demonstrating recognition of naturally processed envelope. Also, major histocompatibility complex-incompatible L cells which were infected with vaccinia viruses that encoded H-2Dd, but not H-2Kd, and pulsed with peptide were lysed. This demonstrated the appropriate major histocompatibility complex class I restriction. Treatment of the mice with anti-L3T4 prior to immunization caused a severe depletion of CD4+ lymphocytes, yet it did not decrease the CTL priming. Thus, inactivated B. abortus can induce non-CD4+ cells to produce the cytokines required for CTL induction. We conclude that B. abortus stimulates a cellular as well as a humoral immune response, even in the relative absence of CD4+ helper cells. It may be a particularly useful vaccine carrier in HIV-1-infected individuals or others with impaired CD4+ T-cell function.
我们之前已经表明，用与灭活布鲁氏菌结合的人类免疫缺陷病毒（HIV）衍生蛋白或肽免疫小鼠，可诱导病毒中和抗体的分泌，主要为免疫球蛋白G2a（IgG2a）同种型。此外，布鲁氏菌可激活人类CD4 +和CD8 +细胞分泌γ干扰素。由于这些都是Th1型免疫反应的特征，而Th1型免疫反应与细胞介导的免疫发展相关，因此确定布鲁氏菌结合物是否也能作为载体诱导细胞毒性T淋巴细胞（CTL）反应就显得很重要。为了验证这一假设，我们将来自HIV-1 gp120 MN株V3环的一个含有B细胞和细胞毒性T细胞表位的18个氨基酸的肽与布鲁氏菌结合（布鲁氏菌-MN 18聚体）。该肽的一个10个氨基酸的片段已被证明是由小鼠H-2Dd呈递的最小CTL决定簇。结果发现，用10⁸个布鲁氏菌-MN 18聚体生物体进行两次体内免疫，然后用肽进行体外刺激，可诱导病毒特异性CTL反应。体内启动需要与布鲁氏菌结合，因为当布鲁氏菌仅与肽混合时，不会诱导记忆CTL。用肽脉冲处理的靶细胞以及感染编码HIV gp160的痘苗病毒的靶细胞均被杀死，这表明可识别天然加工的包膜。此外，感染编码H-2Dd而非H-2Kd的痘苗病毒并经肽脉冲处理的主要组织相容性复合体不相容的L细胞被裂解。这证明了适当的主要组织相容性复合体I类限制。免疫前用抗L3T4治疗小鼠导致CD4 +淋巴细胞严重耗竭，但并未降低CTL启动。因此，灭活的布鲁氏菌可诱导非CD4 +细胞产生CTL诱导所需细胞因子。我们得出结论，即使在相对缺乏CD4 +辅助细胞的情况下，布鲁氏菌也能刺激细胞免疫和体液免疫反应。它可能是HIV-1感染个体或其他CD4 + T细胞功能受损者特别有用的疫苗载体。
