Alloreactivity against IE-encoded antigens: evidence of the discrepancy between graft rejection and reactivity of IE-reactive T cells.

Participation of IE antigens (Ag) in immune response as the transplantation Ag was examined. IE- B10.A(4R)(4R; Kk, IAk, IE-, Db) mice could not reject skin graft from IE Ag alone-disparate B10.A(2R) (2R; Kk, IAk, IEk, Db) mice despite intravenous (iv) injection of 2R spleen cells (SC) before or after skin grafting, indicating that graft rejection could not be caused across IE Ag-barrier alone. Furthermore, 4R SC could not induce lethal graft-versus-host disease (GVHD) in supralethally (950 rad) irradiated 2R mice. On the other hand, infiltration of lymphoid cells was observed at the site of transplanted 2R skin in 4R mice. SC of 4R mice unprimed or primed with 2R skin or 2R SC showed the capability to proliferate in vitro in response to 2R Ag. In immunofluorescence analysis of lymph node cells (LNC) of 4R mice injected iv with 2R SC 7 days earlier, IE-reactive CD4+Vbeta 11+ T cells did not change in number, but slightly increased the expression of interleukin-2 receptor (IL-2R). In 2R mice irradiated with 670 rad and injected iv with 4R SC 7 days earlier, 4R-derived CD4+V beta 11+ T cells proliferated, changed to blastoid form, and showed a markedly increased expression of IL-2R. To further investigate the influence of IE alloantigens on transplantation immunity, IL-2 production and anti-class I CTL activity were assayed. The 4R SC capable of recognizing IEk and Dk Ag of B10.BR (Kk, IAk, IEk, Dk) generated levels of both IL-2 and CTL activities higher than those of 2R SC capable of recognizing Dk Ag alone. These results strongly suggest that IE alloantigens indirectly act as the transplantation Ag by the stimulation of IE-reactive CD4+ helper T cells resulting in the differentiation of class I-restricted CD8+ T cells.     

Assignment of a human serum glycoprotein SP-40,40 gene (CLI) to chromosome 8.

SP-40,40 is a serum glycoprotein consisting of two different subunits (alpha and beta) assembled into a dimer by disulfide bonds. Northern blot hybridization, using total RNA from several cell lines, showed that SP-40,40 is expressed in glioblastoma and testicular tumor cells, as well as hepatoma cells. Spot blot hybridization of flow-sorted human chromosomes, using a SP-40,40 cDNA fragment as a probe, localized the gene for SP-40,40 to human chromosome 8. This gene has been given the designation CLI, for complement lysis inhibitor, by the Human Gene Nomenclature Committee.     

Vitronectin and its fragments purified as serum inhibitors of Staphylococcus aureus gamma-hemolysin and leukocidin, and their specific binding to the hlg2 and the LukS components of the toxins.

Staphylococcal gamma-hemolysin and leukocidin are bi-component cytolysins, consisting of LukF (or Hlg1)/Hlg2 and LukF/LukS, respectively. Here, we purified serum inhibitors of gamma-hemolysin and leukocidin from human plasma. Protein sequencing showed that the purified inhibitors of 62, 57, 50 and 38 kDa were the vitronectin fragments with truncation(s) of the C-terminal or both N- and C-terminal regions. The purified vitronectin fragments specifically bound to the Hlg2 component of gamma-hemolysin and the LukS component of leukocidin to form high-molecular-weight complexes with them, leading to inhibition of the toxin-induced lysis of human erythrocytes and human polymorphonuclear leukocytes, respectively. Intact vitronectin also showed inhibitory activity to the toxins. The ability of gamma-hemolysin and leukocidin to bind vitronectin and its fragments is a novel function of the pore-forming cytolysins.     

Corticoidogenic effect of acetylcholine in bovine adrenocortical cells

The effect of acetylcholine (ACh) on corticoidogenesis in primary cultured bovine adrenocortical cells was examined. One hour exposure to 10(-3) M ACh resulted in a stimulative effect on corticoidogenesis in the freshly isolated cells, and the effect of ACh grew intense during primary culture and reached the maximum on day 2. ACh showed the effect at a higher concentration than 10(-6) M. Thus the primary 2-day cultured cells were used. The corticoidogenic effect of ACh was inhibited by atropine but not by hexamethonium. The effect of ACh was dose dependent, and the extracellular Ca++ was obligatory in inducing the effect. These results suggest that the corticoidogenic effect of ACh may be due to an increase in Ca++-influx via muscarinic receptor in adrenocortical cells.     

Expression level of enzymes related to in situ estrogen synthesis and clinicopathological parameters in breast cancer patients

In order to evaluate the importance of estrogen production in tumor and surrounding tissues, we measured mRNA expression levels of 5 enzymes participating to estrogen synthesis in situ and 4 breast cancer-related proteins in 27 pairs of tumor and non-malignant tissues. Steroid sulfatase (STS) mRNA was more frequently detected in tumor tissues rather than in their non-malignant counterparts. Estrogen sulfotransferase (EST) was constantly expressed with high level not only in tumor tissues but also in their surrounding non-malignant counterparts. In contrast, mRNA expression levels of aromatase, and 17β-hydroxysteroid dehydrogenase type I and II were relatively low and detected only in small proportion of the patients. We also measured the mRNA expression levels of the same nine genes in tumor tissues of 197 breast cancer patients, and analyzed relationship between the mRNA expression level and the clinicopathological parameters. The mRNA expression levels of STS, aromatase and erbB2 in tumor tissues increased as breast cancer progressed. The tumoral mRNA expression levels of STS, estrogen receptor β, and erbB2 in patients with recurrence were higher than those in patients without recurrence. Upregulation of STS expression plays an important role in tumor progression of human breast cancer and is considered to be responsible for estrogen production in tumor and surrounding tissues.