Search

Non-human primates have been used to study immune function to a much lesser extent than readily available strains of inbred rodents. Nevertheless, in situations where it might be desirable, but impossible, to study human immune responses in vivo, lower primates could provide an acceptable alternative. In order to extend the knowledge of T- and B-lymphocyte function in lower primates, the common marmoset Callithrix jaccus was used as an experimental model. The functional similarities between this species and humans at the level of T-B co-operation in the antibody response were examined, and xenoreactive T-lymphocyte clones were obtained from marmoset spleen cells using Epstein—Barr virus (EBV)-transformed human B cells as stimulators. These clones could act as helper cells when co-cultured with human B lymphocytes, inducing the secretion of both IgM and IgG. Lymphokine production by mitogen-stimulated marmoset T-cell clones was also examined. Interleukins (IL) 2 and 4 activities were detected in clone supernatants using bioassays and interferon-gamma (IFN-γ) was detected using a solid-phase ELISA system. However, SDS—PAGE analysis of biosynthetically labelled marmoset and human T-cell clone supernatant proteins revealed major differences between the soluble T-cell products of the two species. The proliferative responses of marmoset T and B cells to recombinant human IL-2 and IL-4 were also examined. Stimulation of [3H]thymidine uptake was detected in both T cell- and anti-IgM-stimulated B-cell cultures with both of the lymphokines. These results suggests that the key components of the antibody response are functionally conserved between lower primates and man and that the common marmoset may be useful as an in vivo model of immune function, particularly with regard to the role of interleukins such as IL-2 and IL-4. [ABSTRACT FROM AUTHOR]

Peripheral blood mononuclear cells (PBMC) from a patient suffering from the hyper IgE syndrome were used to generate phytohaemagglutinin (PHA)-expanded T-cell clones (all CD4+, CD8-, CD23-). A selection of the clones was tested for their ability to help IgE secretion by culturing with normal B cells in the presence of solid-phase antibody to CD3. Supernatants were harvested on Day 7 and assayed by ELISA for IgE, IgG and IgM. Lymphokine secretion by the clones was assessed by culturing clones for 24 hr with solid-phase antibody to CD3 followed by assay of the supernatants for IL-2, IL-4 and interferon-gamma (IFN-γ) production. In addition, clones were analysed by flow cytometry for CDw29 and CD45R expression. Initial experiments with seven clones indicated that those clones that could help IgE secretion also stimulated optimal IgG and IgM responses. All clones appeared to secrete IL-2, IL-4 and IFN-γ, although the mounts of each varied. These results confirm recent findings that human T-cell clones do not fall into Tinf (Th1) and Th (Th2) type subsets as described in the muse. There was no clear correlation between the lymphokines secreted by the clones and their capacity to help IgE production. However, the helper function of the clones for all isotypes, including IgE, appeared to be related to the level of expression of the surface antigen CDw29. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Phytopathology is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Three cultivars of wheat showing different levels of spontaneous karyotypic instability were studied regarding their stability in vitro for a number of characters, i.e. chromosome structure, gliadin pattern, glume and grain colour, awn type, chlorophyll pigmentation and plant morphology. The progenies of somaclones derived from immature embryos of both aneuploid and euploid plants were used in this study along with foundation seeds and a large number of their sexual progeny in order to discriminate between pre-existent variability and any novel variation induced by the in vitro culture. Only one translocation not described before and a new gliadin pattern were detected which could be ascribed to the effects of tissue culture, suggesting that this technique is not effective for inducing novel variation for breeding purposes in wheat. [ABSTRACT FROM AUTHOR]