Radioimmunoassay for the major structural protein of mason‐pfizer monkey virus: Attempts to detect the presence of antigen or antibody in humans

Abstract

The 25,000 dalton protein of Mason-Pfizer monkey virus (MPMV) was isolated by gel filtration chromatography. In agreement with results from other laboratories, antisera to type-C and the non-type-C bovine leukemia and equine infectious anemia viruses did not precipitate 125I-labelled MPMV p25. In addition, these viruses did not cross-react in a competition radioimmunoassay for MPMV p25. Twenty-one human tissues (15 breast carcinomas, 2 normal breasts, 3 acute myelogenous leukemias and 1 sarcoma) were fractionated by detergent solubilization, ammonium sulfate precipitation, and DE-52 anion exchange chromatography. These methods were shown to be highly effective for purification of MPMV p25. Under assay conditions which minimized incubation damage to the 125I-MPMV p25, all tissues failed to react in the competition radioimmunoassay (RIAT). Two hundred and two human sera or plasma specimens, including those from patients with breast cancer and 33 age-matched controls, from 50 patients with hematologic malignancies, from 12 patients with amyotrophic lateral sclerosis, and from 14 patients with systemic lupus erythematosis, were examined for antibodies to MPMV p25. With the exception of two multiple myeloma plasma which produced artifactual false positive reactions based on hypergammaglobulinemia, a known complication of salt precipitation radioimmunoassays, the remainder of the specimens were negative for evidence of MPMV p25 antibodies.

Evidence of Infection with Simian Type D Retrovirus in Persons Occupationally Exposed to Nonhuman Primates

“…Most of these, however, were carried out in groups of patients with specific diagnoses (8,19,25) or in populations with no specific exposure to NHPs (4,26,27). For the majority of these studies, the results have been inconclusive, describing only partial seroreactivity, most commonly to a single SRV gag gene product (e.g., p25 or p27) by Western immunoblotting (WB) (4,8,19,(25)(26)(27). Type D retroviruses have also been isolated from human cell lines in culture, but the majority of these infections have been attributed to laboratory contamination (13,28).…”

Specificity of human antibodies to oncovirus glycoproteins: recognition of antigen by natural antibodies directed against carbohydrate structures.

“…In the absence of a clearly defined oncovirus of human origin, a number of investigators have approached this problem by investigating human sera for naturally occurring antibodies to oncoviruses of other species. The results obtained have varied from positive to negative or equivocal (3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19) For preparation of soluble radiolabeled viral 70,000-dalton glycoprotein (gp7O), purified virions were subjected to detergent lysis in a buffer containing 0.05 M NaCI, 0.02 M Tris-HCl (pH 7.4), 0.5% Nonidet P40, 0.5% sodium deoxycholate, and 10% Traysylol protease inhibitor (10,000 kallikrein inactivator units per ml) for 30 min at 370C. After the viral lysates were subjected to centrifugation at 100,000 X g for 60 min in a type 50 rotor, the supernatant fractions containing soluble viral proteins, including radiolabeled gp7O, were collected and stored at -70'C until used.…”

“…In the absence of a clearly defined oncovirus of human origin, a number of investigators have approached this problem by investigating human sera for naturally occurring antibodies to oncoviruses of other species. The results obtained have varied from positive to negative or equivocal (3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19). Attempts to resolve discrepancies in the published data have centered around discussions of the lability of certain viral protein probes (14) and the use of special reaction conditions influencing human antibody binding to viral antigens (13,14).…”

Humans have antibodies capable of recognizing oncoviral glycoproteins: demonstration that these antibodies are formed in response to cellular modification of glycoproteins rather than as consequence of exposure to virus.

“…Considerable controversy exists in the literature with respect to the prevalence of antibodies to oncoviruses in human sera, detected by using whole virions (4)(5)(6)(7)(8)(9)(10)(11)(12) or purified viral components as probes (13)(14)(15)(16)(17)(18)(19). Recently, Kurth and Mikschy (20) reported that a large fraction of human sera were capable of precipitating, at relatively high titers, the purified major envelope glycoprotein (gp7O) of the woolly monkey type C virus.…”