Nayla C. Moura

Human T lymphocyte receptor for sheep erythrocytes: Characterization of a specific antiserum and its application in the detection and quantitation of the receptor in a soluble form

Abstract An anti-human T lymphocyte serum specific to the receptor for sheep erythrocytes (E) was produced by immunizing sheep with the complex autologous E-soluble E receptor (ER s ). The soluble receptor (R s ) was obtained by heating human lymphocytes at 45 °C for 1 hr. The anti-R s serum has been shown to inhibit E-rosette formation, to be cytotoxic to T cells, to identify T lymphocytes by indirect immunofluorescence, and to stimulate blastogenesis. The reaction of anti-R s with R s was directly demonstrated by two newly developed methods: agglutination of complexes formed by the treatment of formolized E with R s (EFR s complexes) and adhesion of a protein A producer strain of Staphylococcus aureus to EFR s treated with anti-R s . The anti-R s antibodies could be neutralized by R s present in supernatant of heated peripheral lymphocytes, inhibiting the above reactions and therefore providing methods to quantitate R s in biological preparations. The importance of these assays is that R s plays an immunoregulatory activity, and high levels of R s in serum are associated with depressed cell-mediated immunity.

Quantitation of soluble E‐Receptor of T lymphocytes in serum from HIV‐1 positive patients

Human T lymphocytes carry a membrane receptor for sheep erythrocytes (E) related to the CD2 molecule. The E‐receptor is found in a soluble form (Rs) in serum and can be quantitated by “rocket electrophoresis” using an anti‐Rs serum obtained by immunizing sheep with autologous erythrocytes coated with Rs. Increased serum levels of Rs are found in patients with diseases associated with immunodepression. In the present study, 14 asymptomatic HIV‐1 seropositive individuals were investigated regarding their Rs levels and delayed hyper‐sensitivity skin tests every 3 months for a period of 35 months. All these patients progressed to AIDS in this period. Rs serum levels have also been quantitated in 14 normal individuals. The mean Rs values in normal individuals, asymptomatic, and AIDS patients were, respectively: 4.8 ± 1.5 mm (SD), 9.6 ± 1.9 mm (SD) and 11.3 ± 2.4 mm (SD). An increase of Rs serum levels was observed when we compared normal individuals with CDC‐II and CDC‐IV clinical stage patients (P < 0.05, Mann‐Whitney test) and CDC‐II and CDC‐IV patients, (P < 0.05, Wilcoxon test). We have observed a depressed delayed hypersensitivity response to ubiquitous antigens in CDC‐IV patients. Our results indicate that Rs serum levels can be used as a progression marker in HIV infected patients. J. Clin. Lab. Anal. 11:69–72.