Search

Problem: Human seminal plasma is known to exhibit immunosuppressive activity in seminal plasma., Purpose: The purpose was to characterize immunosuppressive proteins in seminal plasma., Method: Gel filtration fractions of 100 to > 440 kDa were identified that inhibited DNA synthesis and killing activity of interleukin-2 stimulated lymphocytes., Results: The fractions exhibiting immunosuppression also inhibited DNA synthesis in a mink lung cell bioassay commonly used to measure the activity for transforming growth factor beta (TGF-beta). The negative growth activity was diminished by a TGF-beta neutralizing monoclonal antibody. TGF-beta was further detected in the active fractions by Western immunoblot., Conclusions: These results identified TGF-beta as an immunosuppressive protein in human seminal plasma and may provide insight into the role of immunosuppression played by seminal plasma, such as in reproduction and neoplasia.

Analysis of salivary digoxin using a rapid dry chemistry, enzyme-labeled immunometric assay (ELIA) was compared with fluorescence polarization immunoassay (FPIA). Saliva and serum samples were obtained from 40 hospitalized patients who were taking digoxin chronically and from 8 patients just prior to treatment with digoxin. Unstimulated saliva samples were collected from 20 patients; however, saliva volumes from 10 pediatric patients were inadequate to permit analysis by FPIA, and 1 other had unmeasurable concentrations by both methods. Stimulated saliva was collected by having patients chew a small piece of Parafilm for 1-2 min. Salivary digoxin was analyzed using the same procedure recommended for serum digoxin by each manufacturer. There were no significant differences found between ELIA and FPIA determinations of unstimulated or stimulated salivary digoxin, serum digoxin, or saliva/serum concentration ratios. The saliva/serum ratio of the unstimulated group was approximately twice that of the stimulated group (p less than 0.01) by both methods, suggesting that salivary digoxin concentration decreases with increased saliva production rate. Excellent correlations were found between ELIA and FPIA salivary digoxin concentrations and between stimulated saliva and serum concentrations by both assays. Weaker correlations were observed between unstimulated saliva and serum concentrations. There was no evidence of assay interference with either method in eight nondigitalized patients, each taking an average of 6.5 medications. The ELIA appears to provide equivalent results compared with the FPIA for the determination of salivary digoxin concentration. Further investigations are needed before salivary digoxin concentration monitoring can be recommended as an acceptable alternative to serum monitoring.

A previous report described the production of monoclonal antibodies Mu-1, -2, -3, and -4 against colon-specific antigen p. We now report the tissue distribution of the reactive epitopes. Each of the monoclonal antibodies was reactive with epitopes shared by the entire length of the intestine, with Mu-2 and Mu-3 determinants being present in the stomach as well. Mu-1 and Mu-4 appeared to have a more restricted distribution than did Mu-2 and Mu-3, which were present in several nongastrointestinal tissues. Unfortunately, these MAbs were not ideal for in vivo use against colorectal carcinoma. Mu-1 was not present in neoplastic colon tissue, Mu-2 and Mu-4 were reactive with granulocytes, and Mu-3 was reactive with kidney tubules and connective tissue. An additional fusion was performed from which Mu-9 was selected for further study. Among normal adult tissues this monoclonal antibody gave reactivity restricted to the intestines. The stomach and all nonintestinal tissues were negative by immunoperoxidase. Among colon tumors 60% were positive for the Mu-9 epitope. The data suggest Mu-9 may be a good candidate for in vivo targeting of diagnostic and therapeutic agents to colon cancer.

Colon-specific antigen-p (CSAp) is a large molecular-sized protein restricted to normal and neoplastic gastrointestinal tissues and to some mucinous ovarian tumors. Murine monoclonal antibodies (MAbs) were raised against CSAp that was affinity purified with goat polyclonal antibodies from GW-39 human colonic carcinoma xenografts or against the CSAp-producing colon cancer cell line SW-948. Two of the MAbs, designated Mu-2 and Mu-4, recognized a CSAp determinant containing sialic acid, and this epitope was also expressed on bovine submaxillary mucin (BSM). Blocking experiments demonstrated that the Mu-2 and Mu-4 MAbs recognized different determinants. A third MAb, Mu-3, did not cross-react with BSM, but unlike Mu-2 and Mu-4, it did react with human saliva. Reactivity of Mu-3 with saliva did not correlate with major blood group and Lewis-related secretory blood group substances in saliva. This reactivity was not related to sialylated Lewis activity. The fourth antibody, Mu-1, appeared to react with a conformational determinant since its epitope was destroyed by heat treatment or thiol reduction. Enzyme immunoassays have demonstrated that all four epitopes may be expressed on one molecular species.