The availability of cell lines that are transfected with IL-4, IL-5 and IFN-gamma cytokine genes permits the prolonged in vivo delivery of functional cytokines in relatively large doses for the modulation of specific immune responses. Often the transfected cells are xenogeneic or allogeneic to the experimental animal and have to be encapsulated in such a way that no cellular response by the host will be induced. Alginate has proven to be a simple matrix for encapsulating cells under mild conditions suitable for in vivo implantation. Encapsulated cells express the transfected IL-4 gene for at least 14 days after in vivo implantation and were shown to be functional during that period by modulating ongoing IgE responses. The application of adherent growing transfected cells permits dose-response titrations and provides an easy method for local and systemic cytokine delivery. Alternatively, hybridoma cells can be encapsulated and the secreted antibody monitored in the serum. It was found that no host immune response was triggered by alginate encapsulated cells. The efficiency of treatment by encapsulated hybridoma cells was shown to be equivalent to that of injecting purified antibodies.

van Ommen R. Vredendaal AECM, Savelkoul HFJ. Prolonged In Vivo IL-4 Treatment Inhibits Antigen-Specific IgGi and IgE Formation. Scand J Immunol I994;40:l-9 IL-4 is obligatory for primary IgE responses, whereas primary IgGi and secondary IgE responses are partially IL-4 independent. To investigate the effect of IL-4 on the antigen-specific memory formation for these isotypes, BALB/c mice were treated after primary TNP-K.LH immunization with recombinant IL-4 for a period of 4 months. This prolonged presence of a high IL-4 level resulted in increased serum levels of total IgG, and IgE, whereas total IgG2^ did not change. The expression of CD23, but not I-A*", increased on the splenic B cells. IL-4 treatment did not affect the IL-4 production by Con A stimulated spleen cells, whereas it did decrease the IFN-7 production. In the same mice the TNP-specific IgGi and IgE serum levels, however, were decreased. Similar results were found when the antigen was continuously present during the IL-4 treatment. Furthermore, it was shown that IL-4 decreased the formation of IgGj and IgE memory cells. These results point to different effects of IL-4 in regulating antigen-specific and bystander responses.R. van Ommen.

The crucial role of interleukin (IL)‐4 in the induction of murine IgG1 and IgE responses, which are coupled through the process of sequential isotype switching, has been well documented. Whereas IL‐4 is obligatory for the induction of IgE responses, it enhances IgG1 responses. In this study, using neutralizing antibodies, we provide evidence that, besides IL‐4, also IL‐6 is required for obtaining peak IgG1 responses. The mRNA levels of these two cytokines are coordinately expressed in the spleen of mice immunized with trinitrophenol‐keyhole limpet hemocyanin (TNP‐KLH). No IL‐6 requirement was observed for peak IgE responses. The IL‐6 dependence of IgG1 responses was found for both antigenspecific and polyclonal responses. Moreover, it was noted using TNP‐KLH and goat anti‐mouse (GAM) IgD as antigen that polyclonal IgG1 responses are more dependent on IL‐6 than antigen‐specific responses. In vitro experiments revealed that exogenous IL‐6 neither enhanced nor inhibited the IgG1 and IgE production by naive B cells, suggesting that IL‐6 did not interfere with the IL‐4‐induced isotype switch potential. Primary and memory IgG1 responses were both similarly dependent on IL‐6. These observations point to a role of IL‐6 in the terminal differentation of B cells switched to IgG1. Neutralization of IL‐6 did not inhibit either antigen‐specific or polyclonal IgE responses. Therefore, it was concluded that IL‐6 is not involved in the terminal differentiation of B cells switched to IgE. These findings thus provide a distinct role for IL‐6, besides IL‐4, in regulating murine IgG1 responses. The formation of IgE, however, is completely dependent on IL‐4 alone.

Van Ommen R, Vredendaal AECM, Savelkoul HFJ. Secondary IgE Responses In Vivo are Predominantly Generated Via 7i€-Double Positive B Cells. Scand J Immunol 1993;40:491-50I We have recently developed a model in which mice were treated with IL-4 after primary immunization, resulting in elevated tolal serum IgGi and IgE levels, but decreased antigen-specific levels and memory formation for these isotypes. In this report, we describe that these effects of IL-4 are mediated at the B cell and not the T-cell level. Major changes occurred in the 7iC-double positive B-cell population which is increased as a result of IL-4 treatment. Moreover, it is shown that 7ie-double positive B cells can develop in vitro out of 71-positive primed B cells and that these double positive cells can differentiate into IgGr and IgE-secreting cells. The existence of 7ie-double positive memory B cells can explain the differences in cytokine dependence of TNP-specific memory IgGj and IgE responses found after adoptively transferring primed spleen cells into irradiated naive recipients. Whereas the IL-4 independent TNP-specific memory IgGi responses could be blocked efficiently by neutralizing IL-5 and IL-6, TNP-specific memory IgE responses were virtually not susceptible to such treatment. These IgE responses were also not susceptible to IFN-7, used in doses that could inhibit the primary IgE response. Inhibition of the TNP-specific memory IgG 1 response by neutralizing IL-5 and IL-6 is accompanied by a 10-fold increase of the IL-4 independent TNP-specific IgE memory response. These data indicate that secondary IgE responses primarily result from B cells that are either switched lo IgG|, or are double positive for IgG| and IgE, thereby suggesting a minor role for e-single positive B cells in secondary IgE responses.

The aim of this study was to map out the extent of the physical complaints and emotional stress due to diagnostic routines of the infertility work-up. To this end a questionnaire was sent to 96 consecutive couples visiting an infertility clinic of a university hospital. The results indicate that women often have physical complaints as a result of the hysterosalpingography (59%) and the diagnostic laparoscopy (47%) and mostly experience these diagnostic procedures as very stressful. Both the postcoital test and the semen analysis caused a moderate amount of stress. The other diagnostic procedures, including physical examination of both sexes, recording of the basal temperature and taking blood for hormonal determinations, were accompanied by fewer complaints and much less stress. It is concluded that the role of the hysterosalpingography and the diagnostic laparoscopy in the routine infertility work-up needs to be reconsidered in view of the burden they pose to the women involved.