Julie A. Titus

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTMechanism of binding of multivalent immune complexes to Fc receptors. 1. Equilibrium bindingSteven K. Dower, Charles DeLisi, Julie A. Titus, and David M. SegalCite this: Biochemistry 1981, 20, 22, 6326–6334Publication Date (Print):October 1, 1981Publication History Published online1 May 2002Published inissue 1 October 1981https://pubs.acs.org/doi/10.1021/bi00525a007https://doi.org/10.1021/bi00525a007research-articleACS PublicationsRequest reuse permissionsArticle Views243Altmetric-Citations58LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose Get e-Alerts

Receptors used by natural killer (NK) cells to mediate natural cytotoxicity are poorly defined, although it is now clear that a number of adhesion molecules can serve this function. CD38 transduces signals on T- and B-cell lines, and we asked whether it could trigger lytic and secretory responses in human NK cells. By using an anti-CD38 monoclonal antibody in reverse antibody-dependent cellular cytotoxicity experiments, it is shown that CD38 engagement triggers cytotoxic responses by activated NK cells, but not by cytotoxic T lymphocytes or fresh NK cells. Cross-linking with anti-CD38 F(ab')(2) caused activated NK cells to release granzymes and cytokines, but did not trigger an increase in intracellular Ca(2+). Fresh NK cells acquired CD38-dependent lytic function during activation with interleukin-2 (IL-2), and inhibitor studies suggested that IL-2 stimulated the de novo expression of proteins that act between CD38 and the lytic machinery in NK cells. The induction of proteins that link commonly expressed adhesion molecules to effector mechanisms could provide a paradigm for pathogen recognition by the innate immune system.

Abstract Murine myeloma proteins of the four IgG subclasses and of the IgA and IgM classes have been examined for their ability to inhibit the binding of affinity cross-linked trimeric rabbit IgG to various types of murine cells. In addition, proteins of the IgG1, IgG2a, and IgG2b subclasses have been cross-linked with dimethyl suberimidate and the purified oligomers have been tested for direct binding. With a macrophage line (P388D1), a lymphocyte line (AKTB-1), and normal spleen cells, proteins of the IgG1, IgG2a, and IgG2b subclasses all compete for binding at the same site. Differences in binding affinities between proteins of the IgG1, IgG2a, and IgG2b subclasses are small and are not greater than differences in affinities when proteins within a subclass are compared. Proteins of the IgG3 subclass and the IgM and IgA classes do not significantly inhibit IgG binding at the highest concentrations tested. P388D1 cells are also able to bind iodinated monomeric IgG2a proteins with higher affinity than expected from inhibition studies. This binding is inhibitable by proteins of the IgG1, 2a, and 2b subclasses, and is trypsin sensitive. These results could be explained by the existence of a second type of receptor, or by assuming that the iodination procedure increases the affinity of IgG2a proteins for P388D1 cells.