Chromosome abnormalities of porokeratosis-cultured epidermal keratinocytes. Comparison with those of cultured dermal fibroblasts.

Cultured epidermal keratinocytes and dermal fibroblasts derived from porokeratosis (PK) patients' skin lesions or normal-appearing skin had numerical and sometimes structural chromosomal abnormalities. Such abnormal cells were seen in 4.08% and 0.375% of all the studied epidermal keratinocytes derived from affected skin and normal-appearing skin, respectively. Similar abnormalities were present in 1.70% and 3.67% of the dermal fibroblasts from the patients' affected skin and normal-appearing skin, respectively. Chromosomal abnormalities were more frequent in keratinocytes and fibroblasts from the patients' skin than in keratinocytes (0.429%) or in fibroblasts (1.22%) derived from normal control donors. Clonal proliferation of such abnormal cells was frequently seen in keratinocytes from the patients' affected skin. The frequent appearance of chromosomal abnormalities and clonal proliferation in epidermal keratinocytes may explain skin lesion formation and skin cancer development in PK patients.     

Immunosuppressive dose of azathioprine inhibits replication of human cytomegalovirus in vitro

Summary Azathioprine (Aza) was found to have anti-human cytomegalovirus (HCMV) activity in vitro at concentrations used for immunosuppression therapy. The dose of Aza for 50% plaque reduction was 0.592µg/ml for HCMV in human embryonic lung (HEL) cells, but those of Aza for 50% plaque reduction for herpes simplex virus (HSV) and varicella-zoster virus were more than 20µg/ml. The dose of Aza for 50% reduction of the HCMV yield in infected cells was 0.25µg/ml, while that for 50% reduction of the HSV yield in infected cells was more than 50µg/ml. The dose of Aza for 50% growth inhibition of HEL cells was 30µg/ml, and 50.7 and 120 times greater than the doses for 50% reduction of the plaque formation and the yield of HCMV, respectively. Thus Aza was found to have a strong anti-HCMV activity at concentrations used for immunosuppression. When HCMV infected cells were treated with cyclosporine (CsA: 0.2µg/ml) and prednisolone (Pred: 0.3µg/ml) simultaneously with Aza, the doses of Aza for 50% reduction of plaque formation and the yield of HCMV were 0.73 and 0.32µg/ml, respectively. Thus an inhibitory effect of Aza was also observed in HCMV-infected cells treated with CsA and Pred at their concentrations used for immunosuppression. Maintenance of an anti-HCMV dose of Aza in combination with CsA and Pred might establish not only satisfactory immunosuppression but also suppression of HCMV infection in transplant recipients.     

Effect of Delayed-Type Hypersensitivity Reaction and Transferred Lymphokine on the Resistance of Mice to Salmonella typhimurium Infection

Immune mice which exhibited a delayed-type hypersensitivity reaction to bovine serum albumin after bovine serum albumin immunization and stimulation and normal mice that had been transferred with a lymphokine-rich fraction from the supernatant of concanavalin A-stimulated spleen cell cultures demonstrated resistance to Salmonella infection.     

α2-Macroglobulin secretion enhanced in rat hepatocytes by partially characterized factor from Kupffer cells

Isolated rat Kupffer cells produced a factor which stimulated the synthesis of ₂-macroglobulin (2M) in primary cultured rat hepatocytes. Although Kupffer cells placed in culture produced the factor without stimulation by lipopolysaccharide (LPS), the LPS-stimulated cells produced larger amounts of the factor. On the other hand, the production of the factor was inhibited by addition of actinomycin D. The induction of2M synthesis by cultured hepatocytes was enhanced in the presence of dexamethasone (Dex), in that hepatic synthesis of2M increased by addition of the factor alone and with Dex 1.5 and three- to four-fold, respectively. The factor was nondialyzable and stable at 60°C for 30 min. When the factor was fractionated using the molecular sieve method, the activity recovered in the fraction had a molecular weight of over 30,000.     

T cell immunity and primary biliary cirrhosis

T lymphocytes play a pivotal role in the autoimmune response in primary biliary cirrhosis (PBC). Recent studies have shown that there is overlapping in the PDC-E2-specific T and B cell epitopes. In addition, helper T and cytotoxic T cell epitopes all contain a shared peptide sequence. In addition, recognition of exogenous antigens including bacterial antigens by autoantigen-specific T cell and the mechanism of molecular mimicry provide a clue to clarifying the pathogenesis of PBC. Furthermore, the findings that autoantigen-immune complexes cross present and also that the presentation of autoantigen is of a higher relative efficiency, define a unique role of autoantibodies in the pathogenesis of the autoimmune disease. The mechanism of immune-mediated bile duct damage in PBC, including the possible role of T cell-mediated cytotoxicity and molecular mimicry is discussed.     

Emergence of a unique O3:K6 clone of Vibrio parahaemolyticus in Calcutta, India, and isolation of strains from the same clonal group from Southeast Asian travelers arriving in Japan.

Active surveillance of Vibrio parahaemolyticus infection among hospitalized patients in Calcutta, India, was initiated in January 1994. The incidence of cases of V. parahaemolyticus infection suddenly increased in February 1996 and has remained high since then. One hundred thirty-four strains of V. parahaemolyticus isolated from January 1994 to August 1996 were examined for serovar, the presence of the thermostable direct hemolysin gene (tdh) and tdh-related hemolysin genes (trh1 and trh2), production of urease, and antibiogram. Strains of the O3:K6 serovar appeared for the first time in February 1996. The O3:K6 serovar strains accounted for 50 to 80% of the strains isolated during the high-incidence period (February to August 1996). All of the serovar O3:K6 strains carried the tdh gene but not the trh genes and did not produce urease. All of the isolates except two were sensitive to all of the antibiotics tested. These and the results of analysis by an arbitrarily primed PCR method indicated that the O3:K6 serovar strains belong to a unique clone. When the O3:K6 serovar strains, isolated from travelers arriving in Japan from Southeast Asian countries, were compared by the arbitrarily primed PCR method, the strains isolated between 1982 and 1993 were distinct from Calcutta O3:K6 while the strains isolated in 1995 and 1996 were indistinguishable from the Calcutta O3:K6 strains. The results suggest that this unique O3:K6 clone may have become prevalent not only in Calcutta but also in Southeast Asian countries very recently. Not only the O3:K6 strains but also the non-O3:K6, tdh-bearing strains isolated in 1996 produced thermostable direct hemolysin at high levels, and thus the level of hemolysin produced does not appear to have influenced the high incidence of serovar O3:K6 strains.     

The critical role of ocular-infiltrating macrophages in the development of choroidal neovascularization

Choroidal neovascularization (CNV) is directly related to visual loss in some eye diseases, such as age-related macular degeneration. Although several human histological studies have suggested the participation of macrophages in CNV formation, the precise mechanisms are still not fully understood. In this study, we elucidated the role of ocular-infiltrating macrophages in experimental CNV using CCR2 knockout (KO) mice, wild-type mice, and C57BL/6 (B6) mice. CCR2 is the receptor of monocyte chemoattractant protein-1, and the number of infiltrating macrophage and the area of CNV were significantly reduced in CCR2 KO mice. Enriched ocular-infiltrating macrophages from B6 mice actually showed angiogenic ability in a dorsal air sac assay. Moreover, their expression of class II, CD40, B7-1 and B7-2 molecules, and the mRNA for potential angiogenic factors, such as vascular endothelial growth factor, basic fibroblast growth factor, and tumor necrosis factor alpha, was also observed. Collectively, we conclude that ocular-infiltrating macrophages play an important role in CNV generation.     

Characterization of host-range and temperature-sensitive mutants of adenovirus type 5 with particular regard to transformation of a hamster embryo cell line (Nil)

Seventeen conditional lethal mutants (7 host-range and 10 temperature-sensitive) of adenovirus type 5 (Ad5) were classified by complementation test and characterized physiologically in viral-DNA synthesis, induction of cell DNA synthesis (in hamster kidney cells), capsid polypeptides production, and transformation of Nil cells (a hamster embryo cell line) under the restrictive conditions.Seven host-range (hr) mutants were divided into six groups by complementation test and into three classes by phenotypic characterization. Mutants assigned to class III (complementation groups D, E, F) were positive in viral-DNA synthesis and capsid polypeptides (hexon, penton base, fiber) production, and showed some degree of leakiness. Class II mutants (complementation groups B, C) were positive in viral-DNA synthesis with a small amount of capsid polypeptides production. Class I mutant (complementation group A) was an early mutant defective in viral-DNA synthesis but positive in induction of host-DNA synthesis. Transformation of Nil cells was observed with classes I and II mutants and not with class III mutants.Ten temperature-sensitive (ts) mutants were divided into seven complementation groups and into five classes by the available phenotypic criteria. Class V mutant (complementation group G) was positive in viral-DNA synthesis and capsid polypeptides production with extreme leakiness. Class IV mutants (complementation groups E, F) were positive in viral-DNA synthesis and capsid polypeptides production. Class III mutants (complementation groups C, D) were quite similar to class IV except for reduced hexon production. Class II mutants (complementation group B) were early mutants defective in viral-DNA synthesis but positive in induction of host-DNA synthesis. Class I mutants (complementation group A) were similar to class II but with a reduced degree of induction of host-DNA synthesis. Transformation of Nil cells was observed with classes II, III, and IV mutants and not with I and V mutants.In brief, the phenotypic characterization of hr and ts mutants in infection of hamster cells showed a good correlation between complementation grouping and the defective function. Transformation of Nil cells was observed with most groups of the mutants except for the apparently leaky late groups and one group of early mutants under the restrictive conditions.     

An enzyme-linked immunosorbent assay for immune complex of HTLV-I

A sandwich enzyme-linked immunosorbent assay (ELISA) for immune complexes of human T cell leukemia virus type I (HTLV-I) was developed using monoclonal antibody (MoAb) 3G1 which recognizes a different epitope on HTLV-I to that with which natural human anti-HTLV-I antibody binds. The assay was capable of titrating artificial immune complexes not only at antigen-antibody equivalence but also at antibody excess. Although the antigen-antibody ratios could not be determined in the individual sera from patients with overt ATL, the level of immune complexes in three out of four sera was estimated to be 250 +/- 36 ng/ml. Immune complexes of HTLV-I could not be identified in sera obtained from one patient with overt ATL, three healthy HTLV-I carriers and three normal human controls.