Response of peripheral blood mononuclear cells to conditioned medium from cultured oral squamous cell carcinomas

The current study investigated the capacity for tumor factors secreted by head and neck squamous cell carcinoma (HNSCC) cell lines, KB, KB16, and HEP, to induce the secretion of various cytokines from peripheral blood mononuclear cells (PBMCs). PBMCs were isolated from blood samples collected from six healthy volunteers and these cells were incubated for 6, 24, 48, or 72 hours in the presence of 50 percent conditioned medium collected from cultured cell lines pretreated with, or without, stimulants such as phytohemagglutinin (PHA) or lipopolysaccharides (LPS). Aliquots of each supernatant were then assayed for levels of IFN-Γ, vascular endothelial growth factor (VEGF), TNF-α, and IL-4 using enzyme linked immunosorbent assays (ELISAs). Data collected were analyzed using Student's t-test, an ANOVA test followed by Tukey's test, and tests of Pearson's Correlation. PBMCs cultured with KB16-conditioned medium produced the highest levels of IFN-Γ. VEGF was also detected in conditioned media collected from all of the squamous cell carcinoma (SCC) cell lines used, and a significant difference in VEGF levels between control and KB- or KB16-conditioned media was observed. TNF-α was secreted by all PBMC groups within 6 hours of receiving conditioned media, and these levels increased up to the 24 hour timepoint, after which levels of TNF-α stabilized. In contrast, none of the supernatant samples contained detectable levels of IL-4. In combination, these data suggest that direct contact between fresh human PBMCs and conditioned media from tumor cells induces the secretion of TNF-α and VEGF by PBMCs, and this represents an initial angiogenic response.

Immune responses to human papilloma viruses.

HPV infection in the genital tract is common in young sexually active individuals, the majority of whom clear the infection without overt clinical disease. However most of those who develop benign lesions eventually mount an effective cell mediated immune response and the lesions regress. Regression of ano-genital warts is accompanied histologically by a CD4+ T cell dominated Th1 response; animal models support this and provide evidence that the response is modulated by CD4+ T cell dependent mechanisms. Failure to develop effective CMI to clear or control infection results in persistent infection and, in the case of the oncogenic HPVs, an increased probability of progression to CIN3 and invasive carcinoma. The central importance of the CD4+ T cell population in the control of HPV infection is shown by the increased prevalence of HPV infections and HGSIL in individuals immunosuppressed as a consequence of HIV infection. The prolonged duration of infection associated with HPV seems to be associated with effective evasion of innate immunity as reflected in the absence of inflammation during virus replication, assembly and release, and down regulation of interferon secretion and response thus delaying the activation of adaptive immunity. Serum neutralising antibody to the major capsid protein L1 usually develops after the induction of successful cell mediated immunity and these antibody and cell mediated responses are protective against subsequent viral challenge in natural infections in animals. Prophylactic vaccines consisting of HPV L1 VLPs generate high anti L1 serum neutralizing antibody concentrations and in clinical trials have shown greater than 95 per cent efficacy against both benign and neoplastic genital HPV associated disease. These vaccines are delivered intramuscularly and therefore circumvent the immune evasion strategies of the virus.

Effect of N-acetyl-L-cysteine on cytokine production by human peripheral blood mononuclear cells

This study investigates the in vitro effect of the antioxidant drug, N-acetyl-L-cysteine [NAC], on cytokine production by peripheral blood mononuclear cells [PBMC]. PBMC were isolated by Ficoll-Hypaque, and stimulated with anti-CD3 antibodies, phytohaemagglutinin [PHA], lipopolysaccharide [LPS] for 24 hours in the presence or absence of 5 mM NAC. The cytokines produced were measured by enzyme-linked immunosorbent assay [ELISA]. Treatment with NAC significantly up-regulates the secretion of IL-1beta, IL-5 [interleukin] and IFN-gamma [interferon] and down regulates IL-10 production, after anti-CD3 or PHA [p<0.05], but not after LPS stimulation. NAC also significantly increased total IL-12 secretion after anti-CD3 [but not PHA or LPS] stimulation and IL-12p40 after anti-CD3, PHA, and LPS stimulation [p<0.05]. These results indicate that NAC up-regulated the production of pro-inflammatory cytokines, and down regulated anti-inflammatory cytokine production by PBMC, in a process which may be associated with increased levels of glutathione [GSH]. Further work is required to determine whether this increase or decrease in cytokine production is due to direct effect of NAC

Interferon in viral liver diseases: pharmalogical aspects

Descreveram-se os principais tipos de Interferon (IFN) fundamentais. Os IFN alfa, beta e gama foram comparados quanto a origem de açäo. Os principais tópicos analisados foram: receptores, vias metabolicas, proteinas induzidas pelo IFN, efeitos imunes, anticorpos anti-interferon e outros efeitos. Efeitos colaterais e farmacocinetica do IFN foram também analisados