This pattern of cytokine secretion suggested that LT-IIc stimulates both Th1 and Th2 immune responses. from mice that experienced received LT-IIc as a mucosal adjuvant. In contrast, secretion of IL-10 was suppressed in those cells. This pattern of cytokine secretion suggested that LT-IIc stimulates both Th1 and Th2 immune responses. In contrast to LT-IIa and LT-IIb, the original users of the type II subgroup that also are mucosal adjuvants, LT-IIc dramatically enhanced secretion of IL-1 and IL-1 in peritoneal macrophages that had been co-cultured with LPS. Furthermore, the B pentameric subunit of LT-IIc augmented uptake of Ag by bone marrow-derived dendritic cells to levels that exceeded those attained by use of LPS or by the B pentamers of LT-IIa or LT-IIb. These data confirmed that LT-IIc is usually a strong mucosal adjuvant with immunomodulatory properties that are distinguishable from those of LT-IIa and LT-IIb and 3-Aminobenzamide which 3-Aminobenzamide has immunomodulatory properties that may be exploitable in vaccine development. Keywords:heat-labile enterotoxin, mucosal immunology, adjuvant, IL-1, IL-17, IFN- == INTRODUCTION == The oral/gastrointestinal, nasopharyngeal, respiratory, and vaginal mucosae are constantly confronted with antigenic substances from the environment. The vast majority of those substances are harmless and, in most cases, the mucosae are unresponsive 3-Aminobenzamide to those antigens (Ag) or respond only in a muted manner (15). The various mucosae, however, represent natural sites for access of many human pathogens. Protection against those pathogens requires the use of vaccines to evoke strong pathogen-specific, protective immune responses around 3-Aminobenzamide the mucosae. Regrettably, the same endogenous immunoregulatory systems in the mucosae that suppress immune responses to harmless environmental Ags also suppress immune responses to potentially protective Ags. To overcome or bypass those natural immune barriers in the mucosae, mucosal adjuvants are required (5,7,28,29). Users of the A1B5family of oligomeric ADP-ribosylating heat-labile enterotoxins (HLT) (14) have been shown to be potent systemic and mucosal adjuvants (5,18). Based on similarities and differences in genetic, biochemical, and immunological characteristics, the family is usually divided into two major subfamilies (5,14). Cholera toxin (CT) produced byVibrio choleraeand heat-labile enterotoxin (herein referred to as LT-I) produced by enterotoxigenicEscherichia coliare users of the type I HLT subfamily. The users of the type II subfamily (LT-IIa and LT-IIb), are distinguishable antigenically and structurally from your users of the type I subfamily (10,11,14). A compendium of research has demonstrated that this distinctive immunomodulatory activities of LT-IIa, LT-IIb, CT, and LT-I are dependent upon the enterotoxins binding patterns for gangliosides, a family of sugar-containing Rabbit Polyclonal to Claudin 3 (phospho-Tyr219) lipids that are embedded in the plasma membrane of eukaryotic cells (34). Binding of an enterotoxin to its ganglioside receptor(s), directly or indirectly, triggers responses that regulate specific immune functions of T cells, B cells, and/or (DC) cells (1,2,24). The types of responses observed in each of those cells are determined by the ganglioside(s) to which each of the HLT binds (5). CT and LT-I bind with high affinity to GM1(although LT-I also has affinity for an unknown glycoprotein) (32). CT also binds with low affinity (in descending order) to GM2, GD1a, GM3, GT1b, GD1b, and asialo-GM1 (16). LT-IIa binds specifically, in descending order of avidity, to gangliosides GD1b, GM1, GT1b, GQ1b, GM2, GD1a, and GM3(8). LT-IIb binds avidly only to GD1aand to GM2and GM3with much lower affinity (8). Recently, a new HLT was cloned from a strain of enterotoxigenicE. colithat was obtained from the fecal material of a diarrheic ostrich (27). Comparative studies of the predicted amino acid sequences exhibited that the new HLT produced by anE. colicolonizing a non-mammalian host was distantly related to CT or LT-I, but closely related to LT-IIa and LT-IIb (31). The amino acid sequences of the catalytic A polypeptide of the new HLT were very similar to the.
