Highly sensitive enzyme immunoassay for human lymphotoxin (tumor necrosis factor beta) in serum

Quantitative Analysis of Salivary TNF-α in Oral Lichen Planus Patients

Objective. The aim of this study was to quantitatively evaluate the salivary tumor necrosis factor-alpha (TNF-α) level in oral lichen planus patients and to compare the levels of TNF-α between saliva and serum of OLP and controls. Methods. Serum and whole saliva from 30 patients with active lesions of oral lichen planus (OLP) and 30 healthy persons were investigated for the presence of TNF-α by enzyme immunoassay. Student's independent t-test and two-sample binomial proportion test were used to calculate significance of the mean values of TNF-alpha in serum and saliva and to determine the proportions of the detected and nondetected samples in both groups. Results. Proportion of detection and the mean of detectability between saliva and serum of Group B show an almost equal value, which suggests that saliva can be a good alternate to serum to analyze TNF-α in oral lichen planus patients.

Induction of bacillus-Calmette-Guérin-activated killer cells from human peripheral blood mononuclear cells against human bladder carcinoma cell lines in vitro

Cytotoxicity against two human bladder carcinoma cell lines (BT-A and BT-B) was investigated using human peripheral blood mononuclear cells (PBMC) stimulated with viable bacillus Calmette-Guérin (BCG) or sonicated BCG (s-BCG). We applied a cytotoxicity assay based on radioactive labelling of tumour cells by incorporation of L[3H]methionine. The results were compared with the cytotoxicity exerted by lymphokine-activated killer (LAK) cells generated by interleukin-2 (IL-2) and interferon gamma (IFN gamma). BCG-stimulated PBMC showed a cytotoxic potential against BT-A and BT-B comparable to that of IFN gamma-generated LAK cells, but this did not reach the level of IL-2-generated LAK cells. We termed these cytotoxic effectors BCG-activated killer (BAK) cells. In contrast to their cytotoxicity against bladder tumour cells, BAK cells did not differ from unstimulated PBMC in the killing of K562 cells. Only viable but not sonicated BCG was able to induce cytotoxicity against BT-A and BT-B. We could demonstrate the presence of the cytokines IFN gamma, IL-2, tumour necrosis factor alpha (TNF alpha) and TNF beta in the supernatants harvested during the generation of BAK cells. Monoclonal antibodies neutralizing IFN gamma were able to inhibit BCG-mediated cytotoxicity, giving evidence of the involvement of IFN gamma in the induction of BAK cells. Furthermore, we performed experiments to investigate the cytotoxic potential of distinct cell populations. The cells effective in BCG-activated killing of bladder tumour cells could be localized within the CD8+/CD56+ lymphocyte subset. CD4+ cells and macrophages did not exhibit cytolytic activity. Our findings imply that the activation by BCG of CD8+/CD56+ killer cells might be an important antitumoral mechanism during BCG therapy against superficial urothelial bladder cancer.

Human immunodeficiency virus type 1-specific cytotoxic T lymphocytes release gamma interferon, tumor necrosis factor alpha (TNF-alpha), and TNF-beta when they encounter their target antigens

Human immunodeficiency virus type 1 (HIV-1) infection is associated with elevated levels of inflammatory cytokines in the serum and cerebrospinal fluid of infected persons, but the sources of these proteins as well as the specific stimuli which trigger their production and release have not been fully defined. In this study, we evaluated the ability of HIV-1-specific cytotoxic T-lymphocyte (CTL) clones derived from seropositive persons to release gamma interferon (IFN-gamma), tumor necrosis factor alpha (TNF-alpha), and TNF-beta upon contact with target cells presenting viral antigen. Peripheral blood- and cerebrospinal fluid-derived HIV-1-specific CD3+ CD4- CD8+ CTL clones as well as freshly isolated peripheral blood mononuclear cells from infected persons were tested in parallel for HIV-1-specific cytotoxicity and cytokine release. Target cells consisted of autologous and allogeneic B-lymphoblastoid cell lines sensitized with synthetic HIV-1 peptides containing the epitopes recognized by these CTL. Cytokine production was measured by specific enzyme-linked immunosorbent assay of culture supernatant fluid. HIV-1-specific CTL clones directed at envelope, Gag, reverse transcriptase, and Nef epitopes specifically released IFN-gamma, TNF-alpha, and TNF-beta upon contact with their relevant target epitopes but not following contact with irrelevant epitopes. These cytokines were released in an HLA class I-restricted fashion, and release was detectable as early as 4 to 6 h of incubation and remained elevated at 48 h. Fresh peripheral blood mononuclear cells from a seropositive person likewise released IFN-gamma in an antigen-specific and HLA class I-restricted manner when incubated with target cells presenting a peptide containing a CTL epitope, paralleling the HIV-specific cytolytic activity of these cells. These studies indicate that in addition to mediating direct cytotoxicity, HIV-1-specific CTL may affect other immune responses by releasing IFN-gamma, TNF-alpha, and TNF-beta. Elevated levels of these cytokines which have been detected in serum and cerebrospinal fluid of infected persons may be due at least in part to the persistent HIV-1-specific CTL response.