Neonatal exposure to antigen is believed to result in T cell clonal inactivation or deletion. Here we report that, contrary to this notion, neonatal injection of BALB/c mice with a hen egg lysozyme peptide 106-116 in putative "tolerogenic" doses induced a T cell proliferative and an immunoglobulin G (IgG) antibody (Ab) response of both T helper cell 1 (Thl)(IgG2a, IgG2b, and IgG3) and Th2-depen...

We studied T-cell clones generated from grafts of rejecting and tolerant animals and investigated the regulatory function of Th2 clones in vitro and in vivo. To prevent allograft rejection, we treated LEW strain recipient rats of WF strain kidney grafts with CTLA4Ig to block CD28-B7 costimulation. We then isolated epitope-specific T-cell clones from the engrafted tissue, using a donor-derived i...

The clinical and pathologic features of classical Hodgkin lymphoma (cHL) reflect an abnormal immune response that is thought to be due to the elaboration of a variety of cytokines by the malignant Reed-Sternberg (RS) cells or surrounding tissues. The majority of cHL cases are characterized by expression of tumor necrosis factor receptor (TNFR) family members and their ligands, as well as an unb...

After birth, the respiratory tract adapts to recurrent exposures to pathogens, allergens, and toxicants by inducing the complex innate and acquired immune systems required for pulmonary homeostasis. In this study, we show that Foxa2, expressed selectively in the respiratory epithelium, plays a critical role in regulating genetic programs influencing Th2 cell-mediated pulmonary inflammation. Del...

BACKGROUND Although the T-cell subset differentiation pathway has been characterized extensively from the view of host gene regulation, the effects of genes of the pathogen on T-cell subset differentiation during infection have yet to be elucidated. Especially, the bacterial genes that are responsible for this shift have not yet been determined. METHODS Utilizing a single-gene-mutation Lister...

LPS potently induces dendritic cell maturation and the production of proinflammatory cytokines, such as IL-12, by activation of Toll-like receptor 4 (TLR4). Since IL-12 is important for the generation and maintenance of Th1 responses and may also inhibit Th2 cell generation from naive CD4 T cell precursors, it has been inferred that TLR4 signaling would have similar effects via the induction of...

Eosinophils are primarily thought of as terminal effectors of allergic responses and of parasite elimination. However, limited studies suggest a more discrete immunomodulatory role for this leukocyte during these inflammatory responses. In this investigation, we highlight the potential of eosinophils to act as APCs and thus modulators of allergic responses by influencing Th2 cell function. In r...

We have described here two distinct types of carrier-specific helper T cells which act independently and synergistically to augment the B-cell response to a hapten. They are separable by passage through a nylon wool column. The first type of helper T cell, which we designate as Th1, is nylon nonadherent, and can help the response of hapten-primed B cells only if the haptenic and carrier determi...

The differentiation of CD4 T cells into Th1 and Th2 cells in vivo is difficult to analyze since it is influenced by many factors such as genetic background of the mice, nature of antigen, and adjuvant. In this study, we used a well-established model, which allows inducing Th1 or Th2 cells simply by low (LD, 10(5)) or high dose (HD, 10(9)) injection of sheep red blood cells (SRBC) into C57BL/6 m...

A localized Th2 milieu has been observed in the intestine of subjects with food allergic disorders; however, the role of T cells in the pathophysiology of these disorders remains poorly understood. Our aim was to examine sites of T cell activation in response to food challenge, identify potential factors responsible for T cell recruitment to the gut, and determine the role of T cells in disease...