# HEME ACQUISITION BY HAEMOPHILUS INFLUENZAE

> **NIH NIH R01** · UT SOUTHWESTERN MEDICAL CENTER · 1993 · $254,390

## Abstract

A striking feature of the biology of Haemophilus influenzae is that these
organisms can be distinguished from nearly all other facultative,
gram-negative bacteria by their absolute requirement for heme.
Surprisingly little attention has been paid to understanding how this
parasite satisfies this unusual nutritional requirement, especially while
growing in its human host.  This research project involves a
comprehensive approach to this unexplored aspect of H. influenzae
molecular biology and disease pathogenesis.  The ultimate objective of
this research program is the elucidation of the mechanisms used by both
typable and nontypable strains of H. influenzae for the acquisition of
heme, with particular emphasis on how this pathogen obtains heme from the
serum proteins hemopexin and haptoglobin which bind heme and hemoglobin,
respectively, in the human body. 1) The newly identified 100kd protein of
H. influenzae type b, which binds heme:hemopexin complexes and has been
shown to be necessary for utilization of heme bound to hemopexin, will be
investigated for its structure-function relationships.  In addition, the
relationship of this macromolecule to the RTX family of cytotoxins will
be determined. 2) The 51kd heme-binding lipoprotein, which is ubiquitous
among H. influenzae strains, will be investigated to determine its
involvement in transport of heme into the H. influenzae cell.  Additional
experiments will be performed to determine whether this unusual
lipoprotein is a one component of a permease system related to the
superfamily of periplasmic binding protein-dependent, ATP-linked
transporters. 3) Other H. influenzae cell surface constituents involved
in the acquisition of heme from carrier proteins will be identified by
the use of molecular genetic techniques, with special emphasis on the
nontypable H. influenzae proteins involved in this process. 4) The
surface-exposed proteins of nontypable H. influenzae shown to be involved
in the acquisition of heme will be evaluated for their potential for
vaccine development.  This last set of experiments is especially relevant
in view of the lack of a vaccine to prevent both upper and lower
respiratory tract disease caused by nontypable H. influenzae.

## Key facts

- **NIH application ID:** 3127308
- **Project number:** 2R01AI017621-13
- **Recipient organization:** UT SOUTHWESTERN MEDICAL CENTER
- **SAM.gov UEI:** YZJ6DKPM4W63
- **Principal Investigator:** Eric John Hansen
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 1993
- **Award amount:** $254,390
- **Award type:** 2
- **Project period:** 1980-12-01 → 1997-11-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/3127308

## Citation

> US National Institutes of Health, RePORTER application 3127308, HEME ACQUISITION BY HAEMOPHILUS INFLUENZAE (2R01AI017621-13). Retrieved via MORVS 2026-10-25 from https://api.morvs.ai/grant/nih/3127308. Licensed CC0.

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