Resistance to infection: looking for new genes

Area of Science:

• Immunology
• Genetics
• Microbiology

Background:

• Genetic factors in infection resistance are gaining attention after being overlooked.
• Specific genetic abnormalities linked to HLA groups are rare, unlike deficiencies in immunoglobulins or complement.
• Mouse models are crucial for understanding complex gene interactions in infection resistance.

Purpose of the Study:

• To investigate the genetic basis of resistance to intracellular infections.
• To explore the potential identity of genes Ity, Lsh, and Bcg involved in resistance to Salmonella, Leishmania, and Mycobacterium infections.
• To elucidate the role of macrophages as a common factor in resistance to these disparate pathogens.

Main Methods:

• Analysis of gene interactions in inbred mouse strains, including Biozzi high and low antibody-producing lines.
• Experiments with hybrid mice to study the inheritance of resistance and susceptibility genes.
• Comparative analysis of resistance genes across different infectious agents.

Main Results:

• The Ity gene on mouse chromosome 1 is critical for Salmonella typhimurium infection resistance.
• The Ity gene may be identical to Lsh and Bcg genes, which confer resistance to Leishmania donovani and Mycobacterium bovis BCG, respectively.
• High antibody-producing mouse lines are susceptible to intracellular infections, while low antibody-producing lines are resistant, suggesting a genetic link.

Conclusions:

• Macrophages are likely a key common factor in resistance to Salmonella, Leishmania, and Mycobacterium infections.
• Genetic analysis in mice provides a valuable model for identifying similar gene interactions in humans.
• Understanding these genetic factors can lead to novel strategies for combating infectious diseases.