# ROLE OF COMPLEMENT IN ANTIBACTERIAL IMMUNITY

> **NIH NIH R01** · JOHNS HOPKINS UNIVERSITY · 1988 · $180,269

## Abstract

The complement system is composed of a number of plasma proteins which,
when acting in an ordered and integrated fashion, mediate a variety of
important immunological reactions.  Activation of the complement system can
either be beneficial to the host, such as occurs in resistance to microbial
invasion, or it can be detrimental to the host, such as occurs in a variety
of immunopathologic reactions.  The studies proposed in the current
application will focus on two different, but related, aspects of the
complement system and its interaction with invading microorganisms.

The first series of studies will focus on one of the molecular mechanisms
by which the complement system could cause immunopathologic damage to the
host during bacterial infections.  Gram-positive bacteria possess
characteristic polysaccharides in their cell membranes which are called
lipoteichoic acids (LTA).  Lipoteichoic acids possess two characteristics
which may be important in the generation of immunopathologic damage to the
host during bacterial infection.  First, they are secreted by bacteria and
can bind to a variety of host cells.  Second, there is some data suggesting
that LTA is capable of activating the complement system.  Accordingly, we
will determine if LTA is able to bind to host cells and endow them with the
ability to activate the complement system, thereby causing immunopathologic
damage to the host.  Although our initial studies will focus on the
interaction of pneumococcal LTA and erythrocytes, later experiments will
involve LTA from other bacteria, such as streptococci, and other target
cells such as type II alveolar cells and vascular endothelial cells.

The second series of experiments will focus on the role of the complement
system in the host's defense against bacterial infection.  Although six
capsular serotypes of Haemophilus influenzae exist, only one of them, the
type b organism, commonly causes life-threatening systemic disease.  The
complement system plays an important role in the host's defense against H.
influenzae infection.  Accordingly, we will study the interaction of the
different serotypes (a-f) of encapsulated H. influenzae with the complement
system in order to determine if the proclivity of the type b organism to
cause systemic disease is due to a relative resistance on its part to the
defensive functions of the complement system.

## Key facts

- **NIH application ID:** 3124986
- **Project number:** 5R01AI011637-14
- **Recipient organization:** JOHNS HOPKINS UNIVERSITY
- **SAM.gov UEI:** FTMTDMBR29C7
- **Principal Investigator:** Jerry A Winkelstein
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 1988
- **Award amount:** $180,269
- **Award type:** 5
- **Project period:** 1977-06-01 → 1988-11-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/3124986

## Citation

> US National Institutes of Health, RePORTER application 3124986, ROLE OF COMPLEMENT IN ANTIBACTERIAL IMMUNITY (5R01AI011637-14). Retrieved via MORVS 2026-10-25 from https://api.morvs.ai/grant/nih/3124986. Licensed CC0.

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