Rhesus macaque Interleukin-4 (rMamu IL-4)
Also named B cell growth facctor secreted essentially by T helper 2 cells. IL-4 exerts its activity through a high affinity receptor found on B and T cells, mast cells, some macrophage lineages and a variety of non hematopoietic stromal cell lineages. Hence this factor exerts pleiotropic effects on these various targets, including growth induction (T & B cells, myleoid progenitors), thymocyte maturation, enhancement of Ig production, upregulation of MHC class II and FcR expression, etc. IL-4 is also a major regulator of TH-2 differentiation and can dampen the production of the proinflammatory cytokines IL-1, IL-6 and TNF.
Rhesus macaque IL-4 cDNA codes for a aa polypeptide (resulting in a 134 aa mature polypeptide) that is 91.6% homologous to human IL-4 (Genbank accession number L26027). Differences in amino acid sequence between the human and macaque IL-4 are V-22-A (signal sequence), K-26-N, D-28-H, T-30- A, Q-32-R, K-36-E ,E-50-K,V-53-I, F-57-L, N-129-S ,N-135-D and S-152-R, including the loss of a potential N-linked glycosylation site at position 129. However, the 6 cysteine residues confering a high dependence on proper folding are maintained in the macaque sequence. These differences apparently confer some difference in biological activity between the factors from both species (Villinger et al, J Immunol 1995 155:3946-3954).
rMamu IL-4 produced as a mature polypeptide in E coli using the pET32 expression vector with an enterokinase digestion site to ensure the absence of extraneous residues at the aminoterminus. Alternatively, small quantities of rMamu IL-4 can be produced in CHO cells transfected with a pED vector and affinity purified.
Purity is verified by PAGE electrophoresis and absence of endotoxin by LAL test.
Bioactivity of each lot is tested based on induction of either proliferation of the CT4-hs cell line or the expression of CD23 on the surface of RAMOS C6 cell line.
Biological activity levels vary from batch to batch but is generally of the order of 4x106 U/mg.