MORPHOLOGY AND MORPHOGENESIS OF HUMAN IMMUNODEFICIENCY VIRUS-1 ISOLATE, SH01 IN MT4 CELLS
An HIV-1 strain, SH01, isolated by coculture of peripheral blood mononuclear cells (PBMC) was easily passaged in MT4 cell line and multinuclear giant syncytia could be induced in MT2 cells. It was a syncytium-inducing (SI) T-cell-tropic isolate. Electron microscopy showed this isolate shared the typical features of HIV-1 in morphology, such as conical core, variation in size and budding release from cell membrane. A distinct fact was that HIV particles could be found in cytoplasmic vacuoles in MT4 cells infected at 7th day or trasformed persistently with HIV-1 SH01, but cell debris or lysosomes were seen at the same time. So these vacuoles were phagosomes or endocytic vacuoles rather than dilated vesicles of Golgi apparatus or endoplasmic reticulum. Furthermore, a large number of HIV particles were also found by chance in phagolysosomes in HIV-1 SH01-infected MT4 cells at 7th day, but it was quite common in HIV-1 SH01-transformed MT4 cells and the remnants of HIV particles were located in some phagolysosomes, yet the dissolution of phagolysosome membrane could be demonstrated simultaneously. Conclusively, it is evident that HIV particles were taken in by MT4 cells through endocytosis and digested by lysosomes, so the role of lysosomes should be paid attention to more extensively in the clearance of HIV in human body. In addition, a kind of virus-like particles was located in cytoplasmic matrix rather than in vacuoles or vesicles, which were more diversified in size with cores bigger, circular or oval and possibly produced from Golgi apparatus, but their characteristics needs to be further determined.