gp120 is present on the plasma membrane of apoptotic CD4 cells prepared from lymph nodes of HIV-1-infected individuals: an immunoelectron microscopic study.

OBJECTIVE

To study whether free gp120 can be detected on the plasma membranes of apoptotic CD4+ T lymphocytes in lymph nodes from HIV-positive patients.

METHODS

Lymph-node cell suspensions prepared from three HIV-positive patients were studied by pre-embedding, double-immunogold-labeling to identify cell type, determine cell morphology, and detect the presence of bound gp120 molecules. Cells were classified by their surface antigens as helper/inducer T lymphocytes (CD4+), cytotoxic/suppressor T lymphocytes (CD8+), B cells (CD20+), and total lymphocytes [CD45+, leukocyte common antigen (LCA)+].

RESULTS

gp120 colabelled with both apoptotic and normal CD4+ T lymphocytes and LCA+ cells, but not with either apoptotic or normal CD8+ T lymphocytes or B cells. gp120 was more often identified on apoptotic than on normal CD4+ T lymphocytes. The gp120 and CD45 label were often colocalized. HIV particles were not identified to be associated with or budding from either normal or apoptotic lymphocytes.

CONCLUSIONS

Free gp120 is found bound to CD4+ T cells in lymph nodes of HIV-infected individuals and potentially mark them for premature death by apoptosis.