Downregulation of cell surface molecules during noncytopathic infection of T cells with human immunodeficiency virus

Noncytopathic infection of human T-lymphoid cell line CR-10 with human immunodeficiency virus (HIV) (CEM-N1T isolate) resulted in a gradual loss of cell surface receptors for OKT4/OKT4A (HIV receptor), OKT8, OKT3, and OKT11 but not for OKT9 (transferrin receptor) within 10 days after infection. Surface receptor decline was accompanied by a rapid increase in HIV antigens and mRNA expression. Multireceptor downregulation was also observed in three T-lymphoid cell lines (MT-4, CEM, and HBD-1) cytopathically infected with the HIV/N1T virus and in HUT-78 cells infected with the HIV/SF-2 isolate. HIV-infected and uninfected CR-10 cells contained similar levels of mRNAs coding for T3, T8, T9, T11, HLA-A2, and HLA-B7 proteins. By densitometry, fully infected CR-10 cells showed approximately 75% reduction in T4 and tubulin (beta chain) mRNA levels when compared with uninfected CR-10 cells. No such reduction was detected in HIV-infected MT-4 and HBD-1 cells. A T-cell receptor gene (beta chain) rearrangement study revealed that no distinct CR-10 subpopulation was selected out upon infection with HIV. Our results suggest that the reduction in cell surface receptors observed between 1 and 2 weeks postinfection cannot be directly attributed to similar reductions in mRNA levels coding for these receptor proteins. We conclude that HIV infection induces posttranscriptional downregulation of several T-cell surface receptors.

Reconstruction of rectal sphincter by transposition of gluteus muscle for fetal incontinence

Many remedial operations have been described for fecal incontinence. We describe a bilateral gluteus muscle transposition to encircle the rectum with striated muscle. This procedure positions a voluntary muscle around the rectum to produce volitional rectal closure, the opposite direction pulling produces a kinking closure of the rectum, and the newly accentuated anorectal angle also facilitates continence. In 6 incontinent patients, 3 were normalized by this procedure, 1 was improved, and 2 had delayed improvement secondary to the development of a fecaloma. Gluteus muscle transposition may be a useful secondary procedure in that patient with muscle dysfunction deficiency fecal incontinence.