Cloning and expression of Bos indicus interleukin-4 in mammalian cells.

Dendritic cells (DC) which are located at the interface of innate and adaptive immunity are targets of infection by many RNA and DNA viruses. Advances in the ex vivo generation of monocyte derived non proliferating dendritic cells have been used for clinical application like immunotherapy. IL-4 cytokine plays essential role in the maturation and generation of DCs. Bos indicus interleukin 4 (boIL-4) 408 bp was amplified from PBMC’s and cloned in pBSIIKS+ vector. The sequence analysis showed N terminal 69 bp signal sequence and one N-glycosylation site. The phylogenetic tree analysis showed that Bos indicus IL-4 is closely related to the ruminant IL-4 and least sharing of genetic line of human and mouse IL-4. The recombinant boIL-4 protein was expressed in CHO cells which secreted a 16 kDa protein which was confirmed by SDS PAGE and western blotting. The rec-boIL-4 protein proliferated the bovine PBMC’s, decreased production of nitric oxide in antigen stimulated macrophages, and phagocytosed the micro particles confirming its activity on dendritic cells.

Processing of multimer FMD virus VP1-2A protein expressed in E. coli into monomers.

Expressions of several genes in bacteria were carried out by independent promoter. However, in case of eukaryotes ribosome skipping and introduction of IRES are employed as alternative to multiple translation initiation. Foot and mouth disease virus (FMDV) 2A peptide has been widely used for co-expression of multiple genes in eukaryotic, plant and mammalian systems. The 18 amino acid 2A peptide of FMDV facilitates efficient co-translational dissociation of the polyprotein into discrete protein products. To study the role of 2A in multimeric protein production a construct consisting of tandem repeat of 4 units of C- terminal VP1 linked through 2A sequence was made and expressed in E. coli. Along with tetramer protein, trimer, dimer and monomer proteins were produced. Stability studies showed that the tetramer protein was cleaved to smaller monomer on storage. The results provide scope for using FMDV 2A for expressing multiple genes under a single promoter in prokaryotes.

Nucleotide sequence of DR-B exon of major histocompatibility complex from an Indian zebu cattle breed.

The Indian cattle is known to be more tolerant to tropical infections than the European cattle. In order to verify the genetic basis of this variation, the DR B exon-2 of the major histocompatibility locus, known for coding the antigen recognition site, from the Hallikar breed of Indian cattle was amplified by PCR, cloned and sequenced. Comparison of this sequence with the information available on taurus cattle brought out six unique nucleotide changes and three amino acid changes. The amino acid positions were at 17, 72 and 87. A major variable region was observed at amino acid position 85 to 87 from all the alleles so far reported for the bovine locus.