Anti-tumor necrosis factor alpha F(ab')2 antibody fragments protect in murine polymicrobial sepsis: concentration and early intervention are fundamental to the outcome.

BACKGROUND: Negative results are frequent using anti-TNFalpha antibodies in sepsis models and clinical trials. METHODS AND RESULTS: Different prophylactic doses of anti-TNFalpha F(ab')2 antibody fragments were compared for the prevention of death by sepsis induced by cecal ligation and puncture (CLP) in mice. High (10 mg/kg) and very low (0.01 and 0.1 mg/kg) concentrations of anti-TNFalpha antibody fragments were not the most adequate for treating polymicrobial sepsis, since they did not significantly improve survival. To the contrary, intermediate doses (1 mg/kg) significantly protected the challenged animals. Protective activity was also observed when administration of the antibody fragments was initiated early (up to 30 min) after CLP. CONCLUSIONS: These results suggest that in processes where excessive production of cytokines is involved, the aim should be to return them to their physiologically acting range but not to inhibit their production. The timing of initiating therapy should also be considered in order to maximize the possible benefits.

DIG-ELISA test in onchocerciasis. Serum antibodies and probability of infection.

An immunoenzymatic test (DIG-ELISA) was serologically evaluated for the serodiagnosis of onchocerciasis. Control and infected sera from the onchocerciasis endemic area of Mexico was collected and the donors assessed for onchocerciasis according to parasitological, clinical, and epidemiological data. The sera were submitted to the DIG-ELISA test using a crude extract prepared from O. volvulus adult worms which had been preserved in nodules in 67% glycerol. The test showed a 100% sensitivity with sera from 38 microfilariae carriers and 96% specificity with sera from 133 non-infected people living outside the endemic zone. In addition, seropositivity was 52.9% with samples from non-onchocercotic people living inside the endemic area, while 82.5 and 90.5% of sera from patients with clinical symptoms and subcutaneous nodules, respectively, were positive. A high rate (30%) of cross-reactivity with serum samples from people infected with Wuchereria bancrofti or Brugia timori was obtained, which is in contrast with the low seropositivity rates (7.4%) obtained with sera from patients infected with other parasites. These results suggest that DIG-ELISA test may be a useful serological test for antibody detection in onchocerciasis, especially for epidemiological surveillance of disease, but because of the high cross-reactivity observed, its use must be limited to areas where this parasitic infection does not coexist with other human filariasis. Finally, the arrangement of sera in groups according to the relative likelihood to have onchocerciasis seems to be a useful procedure for evaluation of serological tests.

Successful application of the diffusion-in-gel-enzyme-linked immunosorbent assay (DIG-ELISA) in onchocerciasis.

The recently described DIG-ELISA test was evaluated on 38 sera from patients with onchocerciasis, using a soluble, crude extract of Onchocerca volvulus dissected out from glycerol-preserved nodules. Results showed that the diameters of the orange-yellow antibody-antigen reaction zones obtained with infected sera were significantly greater than those obtained with normal human sera. A close correlation was observed between the diameters of the reaction zones and antibody concentration (expressed as log of the serum dilution), indicating the potential utility of this test in the quantitative determination of serum antibodies. Because the test is easily performed, it can be used under field conditions when an immediate quantitative determination of serum antibodies is needed.