Effects of different HIV strains on thymic epithelial cultures.

The thymus is the major site for T cell development; interactions of developing thymocytes with thymic epithelial cells are critical for normal thymopoiesis. We set out to determine whether thymic epithelial cells can be infected by HIV strains that cause different patterns of disease progression in infected infants. Thymic epithelial cell monolayers were prepared from normal thymus of infants, removed at the time of cardiac surgery. We infected the thymic epithelial cell monolayers with different strains of HIV, including laboratory strains and clinical strains from 3 of our pediatric HIV-infected patients with different patterns of disease progression. We found that different strains of HIV have different ability to infect thymic epithelial cells; the ability to infect thymic epithelial cells may not be directly related to CCR5/CXCR4 usage. Different HIV strains thus appear to employ different mechanisms by which they affect thymic components.