Most in vitro systems for the induction of IgE production by human B cells require both IL-4 and the presence of T cells. Little is known about the mechanism of T cell help or the ability of ...different T cell subsets to provide this helper activity. In the present study we demonstrate that, in the presence of exogenous IL-4, anti-CD3 stimulated naive T cells (CD4+CD45RA+) are potent helper cells for human IgE production. In their presence, as little as 750 autologous B cells can produce up to 100 ng/ml IgE. This response was found over a broad range of anti-CD3 concentrations. IgE helper activity by naive T cells was inhibited by IL-2. Under all conditions tested, naive T cells were unable to provide help for IgM production. This is in contrast to activated memory T cells (CD4+CD45RO+), which are very efficient helper cells for IgM or IgE production, provided that IL-2 or IL-2 plus IL-4 are present respectively.
: Cell trafficking into the rheumatoid synovium is thought to play an important role in the inflammation seen in rheumatoid arthritis. Chemokine receptors play a central role in this process, and ...several common variants are known, including the CCR2 variant, CCR2–64I, and two variants of the CX3CR1 gene, V249I and T280M. All three variants result in functional amino acid substitutions. We studied the association of these chemokine receptor variants with susceptibility to and severity of rheumatoid arthritis in two Dutch patient populations; 282 consecutive rheumatoid arthritis patients from a rheumatology outpatient clinic, and a cohort of 101 female rheumatoid arthritis patients, followed closely for a 12‐year period, from whom hand and feet X‐rays taken at three year intervals were scored and analyzed in this study. Although there was a trend towards increased severity of disease in patients carrying CX3CR1 variants, this was not independent of known risk factors. We found no evidence for a significant independent role for the CCR2 and CX3CR1 variants in the susceptibility to or severity of rheumatoid arthritis.
Five ampouled preparations of interleukin-4 (IL-4) have been evaluated by 36 laboratories in 14 countries for their suitability to serve as an international standard for this material in a joint ...international collaborative study for interleukin-3 (IL-3) and IL-4. The preparations were assayed in a wide range of in vitro bioassays and immunoassays. It is clear from the study that different recombinant preparations of IL-4 can have very different biological specific activities, including those from the same source (i.e.,
E. coli). In addition, immunoassay estimates of IL-4 levels did not correlate with those of bioassays, illustrating the fact that immunoassays do not necessarily measure biologically active cytokine. It is of interest that the estimates provided by the different bioassays were less variable than those produced by the immunoassays, suggesting that bioassays can be as accurate, if not more so, than immunoassays. The large reduction in the variability of estimates with the inclusion of a single reference preparation clearly illustrates the need for a single standard to assay IL-4. On the basis of the results reported here, with the agreement of the participants of the study and with the authorisation of the Expert Committee on Biological Standardization (ECBS) of the World Health Organization (WHO) the preparation of IL-4 (
88
656
) was established as the international standard for interleukin-4 with an assigned unitage of 1000 IU/ampoule.
Five preparations of interleukin-3 (IL-3) have been evaluated by 28 laboratories in 12 countries for their suitability to serve as an international standard for this material in a joint international ...collaborative study for IL-3 and interleukin-4 (IL-4). The preparations were assayed in a wide range of in vitro bioassays and immunoassays. It is clear from the biological assays contributed to this study that different recombinant preparations of IL-3 can have very different biological specific activities, including those from the same source (i.e.,
E. coli). Biological assays of IL-3 were significantly more consistent in their estimates of levels of IL-3 than the immunoassays, suggesting an unusual pattern of epitope recognition amongst the antibodies included in the immunoassays. This study also illustrates the point that the level of cytokine measured by immunoassay does not necessarily reflect the biological potency of the cytokine. On the basis of results reported here, with the agreement of the participants of the study and with the authorisation of the Expert Committee on Biological Standardization (ECBS) of the World Health Organization (WHO) the preparation of IL-3 (
91
510
) was established as the international standard for interleukin-3 with an assigned unitage of 1700 IU/ampoule.
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