title: CD28 activation promotes Th2 subset differentiation by human CD4+ cells.
abstract: Ligation of CD28 provides a costimulatory signal to T cells necessary for their activation resulting in increased interleukin (IL)-2 production in vitro, but its role in IL-4 and other cytokine production and functional differentiation of T helper (Th) cells remains uncertain. We studied the pattern of cytokine production by highly purified human adult and neonatal CD4+ T cells activated with anti-CD3, phorbol 12-myristate 13-acetate (PMA) and ionomycin, or phytohemagglutinin (PHA) in the presence or absence of anti-CD28 in repetitive stimulation-rest cycles. Initial stimulation of CD4+ cells with anti-CD3 (or the mitogens PHA or PMA+ionomycin) and anti-CD28 monoclonal antibodies induced IL-4, IL-5 and interferon-gamma (IFN-gamma) production and augmented IL-2 production (6- to 11-fold) compared to cells stimulated with anti-CD3 or mitogen alone. The anti-CD28-induced cytokine production corresponded with augmented IL-4 and IL-5 mRNA levels suggesting increased gene expression and/or mRNA stabilization. Most striking, however, was the progressively enhanced IL-4 and IL-5 production and diminished IL-2 and IFN-gamma production with repetitive consecutive cycles of CD28 stimulation. The enhanced Th2-like response correlated with an increased frequency of IL-4-secreting cells; up to 70% of the cells produced IL-4 on the third round of stimulation compared to only 5% after the first stimulation as determined by ELISPOT. CD28 activation also promoted a Th2 response in naive neonatal CD4+ cells, indicating that Th cells are induced to express a Th2 response rather than preferential expansion of already established Th2-type cells. This CD28-mediated response was IL-4 independent, since enhanced IL-5 production with repetitive stimulation cycles was not affected in the presence of neutralizing anti-IL-4 antibodies. These results indicate that CD28 activation may play an important role in the differentiation of the Th2 subset in humans.
authors.affiliation: Division of Geographic Medicine, Case Western Reserve University, Cleveland, OH 44106-4983.
authors.forename: C L
authors.initials: CL
authors.lastname: King
authors.forename: R J
authors.initials: RJ
authors.lastname: Stupi
authors.forename: N
authors.initials: N
authors.lastname: Craighead
authors.forename: C H
authors.initials: CH
authors.lastname: June
authors.forename: G
authors.initials: G
authors.lastname: Thyphronitis
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D001483:Base Sequence; D018106:CD28 Antigens / Q000502:physiology*; D015496:CD4-Positive T-Lymphocytes / Q000502:physiology; D002454:Cell Differentiation; D002478:Cells, Cultured; D006801:Humans; D015847:Interleukin-4 / Q000096:biosynthesis / Q000235:genetics; D015848:Interleukin-5 / Q000096:biosynthesis / Q000235:genetics; D051379:Mice; D008969:Molecular Sequence Data; D012333:RNA, Messenger / Q000032:analysis; D018418:Th2 Cells / Q000502:physiology*
chemical_list: D000911:Antibodies, Monoclonal; D018106:CD28 Antigens; D015848:Interleukin-5; D012333:RNA, Messenger; D015847:Interleukin-4