Different contribution of co-stimulatory molecules B7.1 and B7.2 to the immune response to recombinant modified vaccinia virus ankara vaccine expressing prM/E proteins of Japanese encephalitis virus and two hepatitis B virus vaccines.

This study clarifies the role of co-stimulatory molecules B7.1 and B7.2 in the immune response to 3 types of vaccines: a/ recombinant modified Vaccinia virus Ankara (MVA) (vJH9) expressing prM/E proteins of Japanese encephalitis virus (JEV), b/ recombinant yeast-expressed Hepatitis B virus (YHBV), c/ human plasma-derived Hepatitis B virus (PHBV). We constructed plasmids expressing B7.1 and B7.2 molecules and found that the expression level of B7.2 protein in transfected CHO-k1 cells was higher than that of B7.1 protein. Mice were co-injected with vaccines vJH9, YHBV and PHBV and plasmids expressing B7.1 or B7.2, respectively, and specific antibody titers for each vaccine were monitored at days 7, 14 and 28 post injection (p.i.). In mice injected with vJH9 vaccine and both B7 plasmids, plasmid B7.2 induced a higher anti-JEV immune response than plasmid B7.1. This implies that the stimulation of the B7.2 immune pathway may be a feasible method of boosting protective immunity against a recombinant viral vaccine. Both B7 molecules were able to induce a specific anti-HBV immune response using YHBV vaccine. On the other hand, B7 molecules had little effect to the specific antibody induction in PHBV vaccination. These results suggested that the contribution of B7.1 and B7.2 molecules in an immune response depended on the character and status of the presenting antigen.

Genetic analysis of the VP1 region of human enterovirus 71 strains isolated in Korea during 2000.

We have isolated Human enterovirus 71 (EV71) from stool and CSF samples taken from patients with acute flaccid paralysis, herpangina, or hand, foot and mouth disease in 2000. Both the cell culture-neutralization test and RT-PCR were used to detect enteroviruses. Rhabdomyosarcoma (RD), HEP2c, and BGM cells were used for the isolation of viruses, and serotypes were determined by the neutralization test using EV71-specific antiserum. For genomic analysis, we amplified a 437-bp fragment of the 5'-noncoding region of the enterovirus genome and a 484-bp fragment of the VP3/VP1 region of EV71 by RT-PCR, with positive results. Products amplified using an EV71-specific primer pair were sequenced and compared with other isolates of EV71. Analysis of the nucleotide sequences of the amplified fragments showed that the EV71 isolates from patients were over 98% homologous and belonged to the genotype C.

Introduction of HIV type 1 subtype E virus into South Korea.

Subtype E HIV-1 is the most prevalent strain in Southeast Asia. Although subtype B is prevalent in Korea, geographical distance and increases in travel may lead to the spread of subtype E in Korea. Therefore, we tried to identify and monitor the patterns of HIV subtype E virus introduction into Korea. The divergence of nucleotide sequences within the envelope region (V3 to V5) of Korean subtype E isolates ranged from 4.3 to 14.6% (n = 8; mean, 9.5 +/- 2.8%). In pairwise comparisons of subtype E isolates between Korea and other regions, the divergence of nucleotide sequences between 8 Korean and 16 Asian subtype E variants ranged from 1.3 to 15.2% (mean, 7.8 +/- 2.6%), whereas the divergence of nucleotide sequences between 8 Korean and 2 African variants ranged from 11.7 to 20.7% (mean, 15.4 +/- 2.2%). A phylogenetic tree showed that Korean subtype E isolates cluster with the Asian isolates but far from the African isolates. These epidemiological and molecular epidemiological data suggest that HIV-1 subtype E strains have been transmitted into Korea from endemic areas of Southeast Asia rather from Africa.

Protection against lethal Japanese encephalitis virus infection of mice by immunization with the highly attenuated MVA strain of vaccinia virus expressing JEV prM and E genes.

Genes encoding the glycosylated precursor of the membrane (prM) and envelope (E) proteins of a Korean strain of Japanese encephalitis virus (JEV) were inserted into the genome of the host-range restricted, highly attenuated, and safety-tested MVA strain of vaccinia virus. MVA recombinants containing the JEV genes, under strong synthetic or modified H5 vaccinia virus promoters, were isolated. Synthesis of JEV prM and E proteins was detected by immunofluorescence microscopy, flow cytometry, and polyacrylamide gel electrophoresis. Mice inoculated and boosted by various routes with either of the MVA recombinants produced JEV neutralizing antibodies, that had titres comparable with those induced by an inactivated JEV vaccine, as well as haemagglutination-inhibiting antibodies. Mice immunized with 2 x 10(6) infectious units of MVA/JEV recombinants by intramuscular or intraperitoneal routes were completely protected against a 10(5) LD50 JEV challenge at 9 weeks of age.

Envelope gene sequence variation among Japanese encephalitis viruses isolated in Korea.

The nucleotide (nt) sequences of the envelope (E) gene of 4 Japanese encephalitis virus (JEV) isolates from Korea (K82PO1, K87P39, K91P55 and K94PO5) were determined and the deduced amino acid (aa) sequences were compared within themselves and with the published sequences of 16 other JEV strains originating from other parts of Asia. Homologies of 87.2 - 95.6% at the nt level and 95.8 - 98.0% at the aa level among the Korean JEV isolates were found. aa positions 89, 129, 220, 225, 327, 366, 456 and 477 characterized the Korean isolates. According to the phylogenetic analysis based on the E gene nt sequence, the Korean isolates formed distinct subgroup consisting of at least 2 genetic types.

Stem cell factor protects bone marrow-derived cultured mast cells (BMCMC) from cytocidal effect of nitric oxide secreted by fibroblasts in murine BMCMC-fibroblast coculture.

The survival of mast cells are dependent on two kinds of growth factors, one derived from T cells (IL-3) and another derived from fibroblasts (stem cell factor [SCF]). The 3T3 fibroblast cell line derived from WCB6F(1-)+/+ mouse embryos (+/+ 3T3 fibroblasts) supported the proliferation of bone marrow-derived cultured mast cells (BMCMC) in the PWM-stimulated spleen cell conditioned medium (PWM-SCM), whereas the 3T3 fibroblast cell line from WCB6F1-Sl/Sld mouse embryos (Sl/Sld 3T3 fibroblasts) did not. To study the role of nitric oxide (NO) on the growth of mast cells in BMCMC-fibroblast coculture, we used a NO synthase inhibitor, NG-monomethyl-L-arginine (NGMMA). NGMMA recovered survival and maintained proliferation of mast cells in BMCMC-Sl/Sld 3T3 fibroblasts coculture. Sl/Sld 3T3 fibroblasts as well as 3T3 fibroblasts from NIH(-)+/+, BALB(-)+/+ or Swiss(-)+/+ mouse embryos secreted NO in PWM-SCM, but not in alpha-MEM. SCF protected BMCMC from cytotoxicity of exogenous NO in IL-3-supplemented alpha-MEM. We concluded that SCF might protect BMCMC from cytocidal effect of NO in BMCMC-fibroblasts coculture.

Incidence and predictors of postextubation laryngeal edema in pediatric patients with congenital heart disease.

Laryngeal edema developed in 10.1% of studied patients with congenital heart disease after cardiac surgery. The 181 patients were divided into two groups; those with laryngeal edema (group 1) and those without laryngeal edema (group 2). The mean ages in group 1 and 2 were 10 and 22.9 months. Group 1 patients were younger on average than those of group 2 (p < 0.05). The differences in the cardiopulmonary bypass time and anesthesia time between the two groups were not statistically significant. The duration of intubations and ventilatory support before and after the onset of laryngeal edema and the period of the ICU stay were longer in group 1 than in group 2 (P < 0.05). A predictor of postextubation laryngeal edema was not found in our patients from above mentioned parameters. We conclude that the higher incidence of laryngeal edema may be due to young age (most were under 1 year of age), and duration of intubation and ventilatory support.

Isoenzymes of creatine phosphokinase in serum of families with malignant hyperpyrexia.

The activity and isoenzymes of creatine phosphokinase (CPK) in the serum of 2 women vulnerable to malignant hyperpyrexia were studied. Serum CPK activity was markedly elevated but, in contrast to a previous report, only skeletal-muscle type CPK activity was present.