Evaluation of commercial HIV test kits used in Nigeria.

BACKGROUND: Accurate and reliable diagnosis of HIV plays a central role in any effective HIV intervention. We decided to evaluate 4 commercial HIV test kits to determine their reliability for use in developing countries. METHODS: Serum samples obtained from clients accessing tertiary health services at the STI clinic, Jos University Teaching Hospital were used to evaluate Sdbioline, Diaspot, Determine and DIALAB Elisa kits. A Western blot was used as the reference kit. RESULTS: DETERMINE kit gave 34 positive and 58 negative reactions and the positive sera were all confirmed by Western blot while DIASPOT kit gave 27 false negative results, which was at variance with the reference kit result. Other kits were SDBIOLINE with 5 false positive and DIALAB Elisa kit, which gave one false positive, and one false negative result. CONCLUSION: We conclude that Determine, SDbioline and DIALAB Elisa kits are reliable for HIV antibody testing in Nigeria and other developing countries.

CheX in the three-phosphatase system of bacterial chemotaxis.

Bacterial chemotaxis involves the regulation of motility by a modified two-component signal transduction system. In Escherichia coli, CheZ is the phosphatase of the response regulator CheY but many other bacteria, including Bacillus subtilis, use members of the CheC-FliY-CheX family for this purpose. While Bacillus subtilis has only CheC and FliY, many systems also have CheX. The effect of this three-phosphatase system on chemotaxis has not been studied previously. CheX was shown to be a stronger CheY-P phosphatase than either CheC or FliY. In Bacillus subtilis, a cheC mutant strain was nearly complemented by heterologous cheX expression. CheX was shown to overcome the DeltacheC adaptational defect but also generally lowered the counterclockwise flagellar rotational bias. The effect on rotational bias suggests that CheX reduced the overall levels of CheY-P in the cell and did not truly replicate the adaptational effects of CheC. Thus, CheX is not functionally redundant to CheC and, as outlined in the discussion, may be more analogous to CheZ.