7 Stress Proteins and Infectious Diseases

Abstract

I. INTRODUCTION
Infectious diseases caused by bacterial and parasitic pathogens remain a major public health problem in most of the developing world. Improvement in the control programs for these diseases requires development of new diagnostic methods and effective prophylactic vaccines. Therefore, considerable effort has been invested in the analysis of pathogenic mechanisms and identification of the individual components of pathogens that are involved in interactions with the host immune system.

Analysis of stress proteins is an important part of two distinct aspects of such studies. First, major antigenic components recognized during a variety of bacterial and parasitic infections have been identified as members of stress protein families on the basis of sequence analysis. Stress proteins therefore have a role as antigens during the immune response to infection. Second, there is evidence that stress protein expression is up-regulated in cells of the host and pathogen during the process of infection. Analysis of the differential expression of stress protein genes is therefore important in understanding factors involved in host/parasite interactions. Both of these aspects are addressed in this chapter.

II. STRESS PROTEINS AS ANTIGENS
A. The Immune Response to Infection
The immune system has a variety of mechanisms for killing and eliminating pathogens. The humoral immune response involves initial binding of antibody to the surface of a pathogen and subsequent killing by complement components in the serum. Cell-mediated immunity requires antigen recognition by regulatory T lymphocytes, which can then activate phagocytic cells capable of engulfing and destroying the pathogen. Regulatory T cells...