Molecular cloning and characterization of Th1 and Th2 cytokines of African buffalo (Syncerus caffer).

The African buffalo (Syncerus caffer) has been implicated as the reservoir of several bovine infectious agents. However, there is insufficient information on the protective immune responses in the African buffalo, particularly in infected animals. In this study, we analysed Th1 cytokines IL-2 and IFN-γ, and Th2 cytokines IL-4 and IL-10. The cloned cDNA of IL-2, IL-4, IL-10 and IFN-γ contained an open reading frame of 468, 501, 408 and 540 nucleotides, encoding polypeptides of 155, 166, 135 and 179 amino acids, respectively. Nucleotide sequence homology of IL-2, IFN-γ and IL-4 was more than 98% between the African buffalo and cattle, which resulted in identical polypeptides. Meanwhile, IL-10 gene of African buffalo and cattle had 95% homology in nucleotide sequence, corresponding to thirteen amino acid residues substitution. Cysteine residues and potential glycosylation sites were conserved within the family Bovinae. Phylogenetic analyses including cytokines of the African buffalo placed them within a cluster comprised mainly of species belonging to the order Artiodactyla, including cattle, water buffalo, sheep, goat, pig and artiodactyl wildlife. A deeper understanding of the structure of these cytokines will shed light on their protective role in the disease-resistant African buffalo in comparison with other closely related species.

Differential transcription of two highly divergent gut-expressed Bm86 antigen gene homologues in the tick Rhipicephalus appendiculatus (Acari: Ixodida).

The transcriptional control of gene expression is not well documented in the Arthropoda. We describe transcriptional analysis of two exceptionally divergent homologues (Ra86) of the Bm86 gut antigen from Rhipicephalus appendiculatus. Bm86 forms the basis of a commercial vaccine for the control of Rhipicephalus (Boophilus) microplus. The R. appendiculatus Ra86 proteins contain 654 and 693 amino acids, with only 80% amino acid sequence identity. Reverse-transcription PCR of gut cDNA showed transcription of only one genotype in individual female ticks. PCR amplification of 3' untranslated sequences from genomic DNA indicated that both variants could be encoded within a single genome. When both variants were present, one of the two Ra86 genotypes was transcriptionally dominant.

Serum total sialic acid and Hanganutziu-Deicher antibody in normals and in cancer patients.

OBJECTIVE: To determine the levels of both TSA and HD antibody in sera of patients with various malignancies and evaluate their potential role as diagnostic and/ or prognostic markers. DESIGN: Laboratory based analysis. SETTINGS: Kenyatta National Hospital, Kenya Medical Research Institute and the Department of Biochemistry, University of Nairobi. SUBJECTS: A total of 909 serum samples, 420 from cancer patients recruited at Kenyatta National Hospital and 509 from normal blood donors recruited at Nairobi Hospital. RESULTS: The mean age for the patients and controls was 36 and 37 years respectively. Carcinoma patients constituted 54%, sarcoma 12.1%, lymphoma 16.4% and 17.4% had other types of tumours. The mean TSA in patients was 0.86 mg/ml +/- 0.026 compared to 0.82 mg/ml +/- 0.014 in controls. The TSA level was significantly higher in patients compared to controls (Student's t-test p = 0.031 at 0.05 confidence level). The TSA increased with age in both study groups. In patient sera, both gender gave the same mean of 0.83 mg/ml while it was 0.82 mg/ml and 0.83 mg/ml in control females and in males respectively. Sarcomas had the highest amount of 0.93 mg/ml but there was no significant statistical variation between tumour types (p = 0.076). The HD antibody mean readings were 0.004 in pathologic sera compared to 0.011 in controls. The values were significantly elevated in patients (p = 0.03) with females giving a higher value for both study groups (p = 0.628). HD antibody readings was significantly higher in carcinomas (p = 0.017) compared to those of sarcomas and lymphomas. There was no association between antibody readings and age of patient (p = 0.601). CONCLUSION: Both TSA and HD antibody values were significantly elevated in patients compared to clinically healthy controls and while TSA levels increased with age and was independent of gender, HD antibody levels were independent of age, gender and also tumour type. The study demonstrates that although TSA is normally elevated in malignancy, most of the sialic acid shed is of N-acetyl type as some patients do not express HD antibody directed to the N-glycolyl sialic acid. The reason why some tumours would express Neu5Gc at any one time needs further evaluation.

Molecular methods for Mycobacterium tuberculosis strain typing: a users guide.

There are now a wide range of techniques available to type Mycobacterium tuberculosis, the problem is to choose the correct technique. For large scale epidemiological studies the portability and standardization of IS6110 restriction fragment length polymorphism (RFLP) means that this remains the gold standard technique. In the next few years the internationally standard mycobacterial interspersed repetitive unit (MIRU) may come to challenge this primacy. Low copy number stains remain a problem and these can be typed by either polymorphic Guanine cytosine-rich repetitive sequence (PGRS) or MIRU-variable numbers of tandem repeat (VNTR). To confirm whether strains are part of a true cluster PGRS remains the method of choice. For local outbreaks and investigations of laboratory cross contamination where speed is of greatest importance suspect strains should be initially investigated using a PCR-based method. The superior reproducibility and discrimination of MIRU-VNTR means that these methods should be favoured. If matches are found, then further confirmation of identity can be achieved using IS6110 RFLP or PGRS if the strains prove to have a low IS6110 copy number.