Effect of a monoclonal anti-lyt-1.1 on the functional activity of precursor, effector, and regulatory cells specific for murine alloantigens.

A monoclonal anti-Lyt-1.1 serum has been characterized in terms of its effect on various cell populations involved in cell-mediated immune responses. The monoclonal serum was compared to a conventionally prepared anti-Lyt-1.1 serum. Cytotoxic T cell precursors and effectors were found to be Lyt-1.1+. Helper T cells which participate in the induction of a cytotoxic response were also Lyt-1.1+ as were suppressor T cells which inhibit cytotoxic responses. The T cell that is required for the production of a nonspecific stimulatory factor, costimulator, and that has been shown to bear the same Ly markers as does the helper T cell, bears Lyt-1.1. Finally, the effector cell which mediates delayed-type hypersensitivity reactions to alloantigens has been shown to be Lyt-1.1+. In all of these cases treatment with the monoclonal anti-Lyt-1.1 and complement had the same effect as did treatment with a conventional anti-Lyt-1.1 and complement. The distribution of Lyt-1.1 on various cell types as determined using the monoclonal anti-Lyt-1.1 is in complete agreement with the Lyt-1.1 distribution obtained with conventional anti-Lyt-1.1 sera, and is quite different from the reactivity of an anti-Thy-1 serum as determined by strain distribution. The distribution of the Lyt-1.1 specificity on the T cells within a given strain is identical to that seen with the conventional anti-Lyt-1.1 serum and, as reported by many others, does not differ from the distribution of Thy-1 specificities.

The ontogeny and turnover kinetics of paternal H-2K antigenic determinants on the allogeneic murine placenta.

In previous reports we provided evidence for the expression of paternal H-2Kk antigens on the placenta, accessible to maternal circulation. We have now examined the ontogeny of paternal H-2Kk antigens in the placenta from day 10 to day 17 of gestation and find a steady increase per gram placenta. In order to substantiate the proposal that the placenta functions as an immunoabsorbent barrier preventing the entry of anti-paternal antibodies to the fetus, we monitored the uptake of monoclonal anti-paternal H-2Kk antibody by target (antigen-bearing) and control fetuses and placentas at various intervals after injection. We have previously shown that F(ab')2 anti-H-2Kk behaves like intact immunoglobulin in placental immunoabsorption studies, and demonstrate here that the peak placental uptake of the antibody is not affected by the removal of the Fc portion, whereas its rate of clearance is increased. In contrast to the anti-H-2Kk antibody, monoclonal anti-I-Ak (specificity 17) antibody (IgG2a) shows no placental immunoabsorption.

Cross-bridge conformation as revealed by x-ray diffraction studies on insect flight muscles with ATP analogues.

The effects of three ATP analogues, alpha,beta-methylene-ATP [ATP(alpha,beta-CH1)], adenosine 5'-0-(3-thiotrophosphate) [ATP(gamma-S)], and beta,gamma-amino-ATP [ATP(beta,gamma-NH)] at various concentrations and temperatures on the X-ray fiber diagrams of glycerinated flight muscles from a water bug (Lethocerus maximus) have been investigated. It is shown that the "relaxed" state can be obtained with all three analogues at high concentrations, the result being particularly clear with ATP(gamma-S). It is inferred that the binding of an ATP-like molecule suffices to produce the relaxed state. At low concentrations ATP(beta,gamma-NH) produces state intermediate between rigor and relaxed which is not simply a mixture of the two. The possible nature of the intermediate is discussed.

Monoclonal antibody against a cryptic carbohydrate antigen of murine and human lymphocytes. I. Antigen expression in non-cryptic or unsubstituted form on certain murine lymphomas, on a spontaneous murine mammary carcinoma, and on several human adenocarcinomas.

This paper describes an IgM monoclonal antibody (49H.8) which was produced following immunization of BALB/c mice with human neuraminidase-treated erythrocytes (NE-RBC). 49H.8 reacts with NE-RBC, neuraminidase-treated T lymphocytes (NE-T) and NE B lymphocytes of both human and murine origin. Little or no reactivity with untreated T or B cells could be detected. Thus the 49H.8 antigen is "cryptic" in most normal lymphocytes of both humans and mice. In contrast, the 49H.8 antigen was detected in non-cryptic or unsubstituted form on many non-treated murine lymphomas of both B- and T-cell origin, on the spontaneous murine mammary carcinoma, TA3-HA and on several human adenocarcinomas. The 49H.8 antigen appears to be related to the previously described 49H.24 antigen as shown by sugar inhibition experiments. 49H.24 reacts most strongly with the synthetic disaccharide (betaGa1 (I leads to 3)alpha Ga1NAc) but not at all with beta Ga1(I leads to 3)beta Ga1Nac. 49H.24 does not react with any of the murine or human tumors tested. 49H.8 reacts with both the alpha and beta forms of the disaccharide but reacts most strongly with phenyl-beta-galactoside-containing compounds. In contrast, phenyl-alpha-galactoside-containing compounds produced no reaction. The natural determinant detected by this antibody was not determined but various possibilities are considered. 49H.8 was used to detect antigen apparently shed from growing TA3-Ha cells into the serum and ascites of tumor-bearing mice. These observations suggest that the 49H.8 monoclonal antibody will be valuable as a specific reagent for a common tumor-associated antigen shared by certain murine and human tumors, and as a means of assaying shed tumor antigen in circulation as in the TA3-Ha mammary adenocarcinoma model.