MHC nonrestricted cytotoxic T cell clones with selective specificity from patients with transitional cell carcinoma (TCC) of the urinary bladder

Summary Lymphocytes from patients with transitional cell carcinoma (TCC) of the urinary bladder are more cytotoxic to bladder tumor cells than to a variety of control cells. This disease-related cytotoxicity has previously been shown to involve several mechanisms and different types of effector cells. To analyze further the nature of the effector cells operative in this system, peripheral blood lymphocytes from eight TCC patients were stimulated in vitro with TCC extract and cultured in the presence of interleukin 2 and allogeneic feeder cells. When tested for cytotoxicity in vitro on a target cell panel including both adherent and nonadherent cell lines, the lymphocytes killed a broad spectrum of targets in a major histocompatibility complex (MHC)-unrestricted fashion. When cloned by limiting dilution, clones were obtained which displayed a more restricted pattern of target cell killing. Some of the clones were highly but not exclusively selective for TCC-derived target cells. Phenotypically, these cells resembled mature T cells of CTL-type (CD8⁺/CD4^–). They also expressed the CD3/5 T cell antigen receptor complex but target cell killing was not MHC-restricted. The results of various inhibition experiments suggested that the CD3/TCR complex was involved in the cytotoxicity exhibited by these effector cells. However, its precise role in target cell recognition and the identification of the tumor cell structures recognised by the effector cells require further studies.     

A p50 surface antigen restricted to human urinary bladder carcinomas and B lymphocytes

Summary We have previously described the derivation of a monoclonal antibody, S2C6, to a novel 50 Kdalton antigen associated with human urinary bladder carcinoma. No reactions were obtained with carcinomas of unrelated origin or with normal urothelial cells. However, the antibody also reacted with a similar antigen on some cell lines of B lymphocyte origin. Using large panels of target cells we have now shown that this reactivity was entirely restricted to cells of the B lineage within the haematopoietic system. As opposed to its apparent restriction to malignant cells of the urothelium, the S2C6 antigen was expressed by normal B lymphocytes as well as by many malignant B cells (chronic lymphocytic leukaemia, hairy cell leukaemia and immunocytoma). Pre-B cells derived from acute lymphocytic leukaemia and plasma cells from multiple myeloma lacked the antigen. Expression was significantly enhanced on cultured B cells from Burkitt lymphomas and on Epstein-Barr virus-transformed lymphoblastoid cell lines including those of the pre-B phenotype derived from fetal bone marrow. As judged from the molecular size and the distribution pattern displayed by the S2C6 antigen it appears to be distinct from other B cell antigens previously described. A possible relation of the S2C6 antigen to a receptor for B cell growth factors is discussed.     

Differential cytotoxicity of activated lymphocytes on allogeneic and xenogeneic target cells. II. Activation by phytohemagglutinin

In the preceding paper it has been shown that human or mouse lymphocytes stimulated by a variety of agents, damaged allogeneic target cells while damage of xenogeneic target cells was weak or absent. In this study, the species specificity of the cytotoxicity of PHA activated lymphocytes has been studied in greater detail. Effector cells were purified lymphocytes either from human peripheral blood, or from spleen or lymph nodes of inbred mice. Target cells were ⁵¹Cr-labeled human Chang liver cells or mouse L cells.PHA stimulated human or mouse lymphocytes were significantly more cytotoxic to allogeneic than to xenogeneic target cells. At low PHA doses at which damage of allogeneic target cells was significant, damage of xenogeneic target cells was very weak or absent. At higher PHA doses, damage of xenogeneic target cells became also significant but always remained at a lower level than that of allogeneic target cells.Prestimulation of human lymphocytes with PHA for 3 days increased their cytotoxic efficiency. Furthermore, damage of human Chang cells by human lymphocytes had a dose-response relationship similar to that valid for stimulation of DNA synthesis. However, damage of mouse L cells by human lymphocytes increased at PHA-doses at which stimulation of DNA-synthesis declined. For mouse lymphocytes, these doseresponse relationships were less clear-cut, probably due to differences in origin and survival of the effector cells. This confirms previous observations that cytotoxicity and DNA-synthesis are different but probably interdependent expressions of lymphocyte activation.     

ANTIGENS IN EGGS AND DEVELOPMENTAL STAGES OF THE SEA URCHIN : I. Immunological and Physicochemical Properties

A number of antigens in unfertilized eggs and embryos of the sea urchin Paracentrotus lividus were characterized with respect to both immunological and physicochemical properties. Experiments involved single diffusion in agar (Oudin technique) combined with mutual dilution, serial dilution, and heating of antigenic extracts, as well as immunoelectrophoresis with normal and heated extracts and agar electrophoresis followed by staining of the antigenic spots with protein specific dyes. The gradual transition in migration rates of bands of precipitates in Oudin tubes following mutual dilution of either extracts or antisera allowed the identification of 6 immunologically identical antigens in eggs and embryonic stages. Similarities with respect to diffusion coefficients, sensitivity to heat, electrophoretic mobility, and reaction to protein specific dyes indicated that the antigens in extracts of eggs and various developmental stages also had certain physicochemical properties in common. Such knowledge is of importance for an understanding of antigenic changes occurring during ontogenesis.     

Biochemical characteristics and partial amino acid sequence of the receptor-like human B cell and carcinoma antigen CDw40

The Ag CDw40 (p50, Bp50) is a phosphoprotein expressed on the surface of both B lymphocytes and on certain malignant cell types of nonhemopoietic origin. Antibodies to this Ag have been shown to act as a potent co-mitogen for B cells. In order to elucidate the function of this Ag, we have now investigated some of its biochemical characteristics as well as the relationship of B cell derived CDw40 to that derived from urinary bladder carcinoma (transitional cell carcinoma, TCC) cells. CDw40 from normal B cells or from the Burkitt lymphoma line Raji showed a characteristic pattern of three bands when analyzed by SDS-PAGE and Western blotting: a main band of 47 kDa, a degradation product of 43 kDa, and a dimer of 85 kDa. The dimer was disrupted by reduction with 2-ME but was reformed spontaneously from the purified monomers under nonreducing conditions. CDw40 from two bladder cancer cell lines gave a similar pattern but formed little or no dimer. Thirty amino acids of the amino terminal end of CDw40 from Raji and 22 amino acids of that from TCC cells (HU549) were sequenced. The sequences were unusually rich in cysteines and differed only in that the cysteine in position 6 in Raji CDw40 had been replaced by glutamine in HU549. In addition there were two conservative changes in positions 15 and 19. Taken together these results show that CDw40 derived from B cells or from TCC cells are the same or closely related molecules. Comparisons of the amino acid sequence and biochemical characteristics of CDw40 with proteins having receptor functions indicated a close structural resemblance of CDw40 to the nerve growth factor-receptor.     

A small camel-milk protein rich in cysteine/half-cystine

A small protein (M_r about 14 000) rich in cysteine/half-cystine has been isolated from camel milk by exclusion chromatography and reverse-phase high-performance liquid chromatography. The N-terminal amino acid sequence shows a region with several positional identities with and -caseins, which however lack cysteine residues; postions 16–20 are identical and involve the serine residues that have been found to be phosphorylated in -caseins.