Mapping of the epitopes of Epstein-Barr virus gp350 using monoclonal antibodies and recombinant proteins expressed in Escherichia coli defines three antigenic determinants

The Epstein-Barr virus (EBV) major surface membrane antigen (MA), gp350/220, induces antibodies that neutralize virus infectivity in vitro. The MA glycoprotein is encoded by nucleotides 1784 to 4504 of the BamHI L fragment of the EBV genome. To define the antigenic epitopes on gp350, sequences encoding portions of the protein were cloned into an Escherichia coli expression system and eight recombinant clones were generated, two overlapping clones representing the C terminus and six overlapping clones representing the N terminus. The epitopes expressed by the recombinant proteins were mapped using 14 anti-MA monoclonal antibodies (MAbs) in a dot blot immunoassay. One of the MAbs reacted with clones that express the C terminus of gp350 and three others reacted with clones expressing the N terminal portion of the protein; the remaining MAbs tested were not reactive with the cloned proteins. The data identify three antigenic determinants on gp350. DNA sequences encoding these epitopes are located between nucleotides 1980 and 2307, 3186 and 3528, and 3528 and 3576 of the BamHI L fragment. In an attempt to elicit neutralizing antibodies, rabbits were immunized with gel-purified recombinant proteins from four of the clones. Neutralization assays indicate that the proteins expressed by these clones do not induce in vitro virus-neutralizing antibodies.

Epitope mapping of the HIV-1 gag region by analysis of gag gene deletion fragments expressed in Escherichia coli defines eight antigenic determinants

Immune response to HIV infection is generally characterized by appearance of antibodies to the gag protein p24 early in infection, and by apparent loss of p24 antibodies accompanied by increases in p24 antigen levels with disease progression. Precise definition of the immunodominant epitopes present in gag gene proteins has potential clinical significance. Seventeen anti-gag monoclonal antibodies (MAb) were used in enzyme-linked immunosorbent assays (ELISA) with antigens expressed by nine recombinant clones to define epitopes on HIV gag proteins which elicit an immune response. All of the MAbs tested, except two anti-p17, reacted with a clone which expresses the carboxyl terminal 13 amino acids of p17 and all of p24 and p15. All anti-p24 MAbs reacted with clones containing all of p24. MAbs reacted differentially with clones containing deleted regions depending on the antigenic portion expressed. Of thirteen potential identifiably different genomic regions which could be predicted from the genomic structure of the clones, eight different antigen epitopes were defined: two on p17, five on p24, and one on p15 (in the region corresponding to the carboxyl terminal protein p6). Six regions did not appear to react with any of the monoclonal antibodies available. Identification of the epitopes present in the cloned antigens should allow their use to evaluate sera from HIV-infected donors at different clinical stages of progression to AIDS.

[Special types of early gastric cancer]

Sixty-seven cases with special types of early gastric cancer collected from 119 early gastric cancer samples resected in our institute from 1964 to 1987 are reported. The pathological and biological features of flat, diffuse and local types, minimal and small types, "one spot" cancer, early multiple cancers and early cancer of gastric stump were analysed The authors believe that thorough understanding these special types of early gastric cancer is of great importance not only in research of histogenesis but also in clinical treatment and prevention of gastric cancer.

An ultrastructural study of the membranoproliferative variant of transplant glomerulopathy

In this study we analyzed the ultrastructural features of the membranoproliferative variant of transplant glomerulopathy in 6 patients from a group of 64 renal transplant recipients who had evidenced graft dysfunction and histological diagnosis of chronic allograft rejection. The principle changes observed by electron microscopy were thickening of glomerular basement membranes by polymorphous changes that included widening of the lamina rara interna by an electron lucent material resembling plasma constituents, replication of lamina densa-like material, and inclusion of microfilaments, membranous profiles, and other cellular remnants. Proliferation of endothelial cells was a prominent finding, suggesting that a reparative endothelial response to injury may be significant to the pathogenesis of this form of transplant glomerulopathy.

[Precancerous lesion and carcinogenesis of stomach cancer]

A research on pathogenesis of gastric carcinoma was carried out by observing microcarcinoma, small carcinoma, early multicarcinoma as well as the mucosa around the cancer. The results show that the site of different types of carcinoma is correlated to the type of gastric dysplasia. In this paper, various types of gastric dysplasia and multicentric histogenesis of gastric cancer are discussed.