# HUMORAL FACTORS OF HOST DEFENSE AGAINST BACTEROIDES

> **NIH NIH R01** · JAMES N. GAMBLE INSTITUTE OF MEDICAL RES · 1992 · $146,514

## Abstract

Our previous studies have demonstrated that the alternative complement
pathway and natural IgM antibodies play an important role in opsonization
and phagocytosis of members of the Bacteroides fragilis group by
neutrophils. Natural IgM antibodies act synergistically with the
alternative pathway to facilitate adherence of the bacteria to neutrophils,
which leads to ingestion and intracellular killing. The studies proposed in
this application will extend these observations by determining the
mechanisms by which natural IgM antibodies act synergistically with the
alternative pathway to promote adherence of B. fragilis and B.
thetaiotaomicron to neutrophils, the structural features of IgM required
for this synergistic activity, the effects of natural IgM antibodies and
the alternative pathway on activation of neutrophils, and the involvement
of natural IgG antibodies in opsonization of these bacteria via the
alternative pathway. Mechanisms responsible for the resistance of highly
encapsulated isolates of the B. fragilis group to opsonization and
phagocytosis by neutrophils will also be determined. These studies will
increase our understanding of the role of natural antibodies and the
alternative pathway in opsonization and phagocytosis of members of the B.
fragilis group by neutrophils. Basic concepts resulting from this research
may also be applicable to bacterial opsonization in general.

## Key facts

- **NIH application ID:** 3129636
- **Project number:** 5R01AI020154-05
- **Recipient organization:** JAMES N. GAMBLE INSTITUTE OF MEDICAL RES
- **Principal Investigator:** ANN B BJORNSON
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 1992
- **Award amount:** $146,514
- **Award type:** 5
- **Project period:** 1983-09-30 → 1994-07-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/3129636

## Citation

> US National Institutes of Health, RePORTER application 3129636, HUMORAL FACTORS OF HOST DEFENSE AGAINST BACTEROIDES (5R01AI020154-05). Retrieved via MORVS 2026-10-25 from https://api.morvs.ai/grant/nih/3129636. Licensed CC0.

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