A primitive T cell-independent mechanism of intestinal mucosal IgA responses to commensal bacteria

AJ Macpherson, D Gatto, E Sainsbury, GR Harriman… - Science, 2000 - science.org
AJ Macpherson, D Gatto, E Sainsbury, GR Harriman, H Hengartner, RM Zinkernagel
Science, 2000science.org
The immunoglobulin A (IgA) is produced to defend mucosal surfaces from environmental
organisms, but host defenses against the very heavy load of intestinal commensal
microorganisms are poorly understood. The IgA against intestinal commensal bacterial
antigens was analyzed; it was not simply “natural antibody” but was specifically induced and
responded to antigenic changes within an established gut flora. In contrast to IgA responses
against exotoxins, a significant proportion of this specific anti-commensal IgA induction was …
The immunoglobulin A (IgA) is produced to defend mucosal surfaces from environmental organisms, but host defenses against the very heavy load of intestinal commensal microorganisms are poorly understood. The IgA against intestinal commensal bacterial antigens was analyzed; it was not simply “natural antibody” but was specifically induced and responded to antigenic changes within an established gut flora. In contrast to IgA responses against exotoxins, a significant proportion of this specific anti-commensal IgA induction was through a pathway that was independent of T cell help and of follicular lymphoid tissue organization, which may reflect an evolutionarily primitive form of specific immune defense.
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