Neutrophils regulate the expression of cytokines, chemokines and nitric oxide synthase/nitric oxide in mice injected with Bothrops atrox venom.

Bothrops atrox crude venom injected intraperitoneal (i.p.) into BALB/c mice induced local afflux of inflammatory cells, one neutrophil-rich peak after 6h and another macrophage-rich peak after 48 h. A similar pattern of local cell afflux plus edema, Delta lesions of some skeletal muscle cells, and hemorrhage were observed in mice intramuscular (i.m.) injected with the venom. Measurement of serum cytokines in neutrophil-depleted (by anti-mouse rat monoclonal antibody (mAb) RB6-8C5) and non-depleted BALB/c mice was performed by ELISA. With the exception of IL-1beta (78 pg/ml), higher levels of IL-6 (1348 pg/ml), MIP-1beta (437 pg/ml) and MIP-2 (904 pg/ml) were observed in neutrophil-depleted mice, in comparison to the values found in non-neutrophil depleted mice: IL-1beta (437 pg/ml), IL-6 (750 pg/ml), MIP-1beta (165 pg/ml) and MIP-2 (90 pg/ml). TNF-alpha was not detected. NO was detected (18 microM) 24h after venom injection in neutrophil-depleted mice. RT-PCR using representative primers detected expression of mRNA in cells from BALB/c mice injected with B. atrox venom: (a) for IL-1beta, IL-6, inducible nitric oxide synthase (iNOS), CXCR2, MIP-2 and RANTES in cells from mice that were neutrophil-depleted or not; (b) for CCR1, CCR5 and MIP-1beta in cells from neutrophil-depleted mice; (c) for MIP-1alpha in cells from non-neutrophil-depleted mice; (d) TNF-alpha and TGF-beta were not detected in either of the mice. These results indicate that neutrophils play a role in regulating the production of some cytokines and chemokines as well as locally expressed or liberated iNOS/NO in tissues injected with B. atrox crude venom.

Suitability of a recombinant Staphylococcus aureus enterotoxin C bovine variant for immunodiagnostics and therapeutic vaccine development.

Recombinant bovine variant of staphylococcal enterotoxin C (SECbovine), produced as a NH2-terminal histidine hexamer fusion protein (His6-tagged SECbovine), expressed at high levels (25%) in Escherichia coli and affinity purified to homogeneity (99.9%), was tested for its diagnostic and therapeutic potentials. His6-tagged SECbovine is antigenically authentic to native SECbovine across host species, as confirmed by antibody-based capture detection assays using human, mouse, rabbit and chicken hyperimmune sera. His6-tagged SECbovine showed significant T-cell stimulation activity in vitro. His6-tagged SECbovine was immunogenic for IgG in mice (intragastric and intravenous routes) and rabbits (intramuscular and subcutaneous routes), dispensing immunoadjuvant coadministration. The formation of neutralizing antibodies reduced the severity of intoxication symptoms in immunized rabbits. Purified anti-recombinant SECbovine rabbit polyclonal IgG neutralized the pyrexic and diarrhoeagenic effects of native SEC/SED and recombinant SEC, tested by the kitten and rabbit bioassays, respectively.

Highly endemic, waterborne toxoplasmosis in north Rio de Janeiro state, Brazil.

In Campos dos Goytacazes, northern Rio de Janeiro state, Brazil, reports of uveitis consistent with toxoplasmosis led to a survey of the prevalence and risk factors for Toxoplasma gondii infection in 1997-1999. The survey population was selected randomly from schools, randomly chosen communities, and an army battalion. Serum samples from 1,436 persons were tested. With results adjusted for age, 84% of the population in the lower socioeconomic group was seropositive, compared with 62% and 23% of the middle and upper socioeconomic groups, respectively (p<0.001). When multivariate analysis was performed, drinking unfiltered water was found to increase the risk of seropositivity for the lower socioeconomic (odds ratio [OR]: 3.0, 95% confidence interval [CI] 1.3 to 6.9) and middle socioeconomic (OR: 1.7, 95% CI 1.2 to 2.3) populations. We also found a high T. gondii seroprevalence in this Brazilian community. Drinking unfiltered water increased the risk of T. gondii seropositivity, indicating the potential importance of oocyst transmission in water in this region.