"Negative vaccination" by specific CD4 T cell tolerisation enhances virus-specific protective antibody responses.

• Main Authors: Karl S Lang, Ahmed N Hegazy, Philipp A Lang, Bruno Eschli, Max Löhning, Hans Hengartner, Rolf M Zinkernagel, Mike Recher
• Format: Article
• Language: English
• Published: Public Library of Science (PLoS) 2007-01-01
• Series: PLoS ONE
• Online Access: http://europepmc.org/articles/PMC2048666?pdf=render

BACKGROUND: Cooperation of CD4+ T helper cells with specific B cells is crucial for protective vaccination against pathogens by inducing long-lived neutralizing antibody responses. During infection with persistence-prone viruses, prolonged virus replication correlates with low neutralizing antibody responses. We recently described that a viral mutant of lymphocytic choriomeningitis virus (LCMV), which lacks a T helper epitope, counterintuitively induced an enhanced protective antibody response. Likewise, partial depletion of the CD4+ T cell compartment by using anti-CD4 antibodies enhanced protective antibodies. PRINCIPAL FINDINGS: Here we have developed a protocol to selectively reduce the CD4+ T cell response against viral CD4+ T cell epitopes. We demonstrate that in vivo treatment with LCMV-derived MHC-II peptides induced non-responsiveness of specific CD4+ T cells without affecting CD4+ T cell reactivity towards other antigens. This was associated with accelerated virus-specific neutralizing IgG-antibody responses. In contrast to a complete absence of CD4+ T cell help, tolerisation did not impair CD8+ T cell responses. CONCLUSIONS: This result reveals a novel "negative vaccination" strategy where specific CD4+ T cell unresponsiveness may be used to enhance the delayed protective antibody responses in chronic virus infections.