Delayed-type hypersensitivity and

Ross, P.S., de Swart, R.L., and Reijnders, P.J.H. et al. (1995). Contaminant related suppression of delayed type hypersensitivity and antibody responses in harbor seals from the Baltic Sea. Environmental Health Perspectives 103, 162. 

A limited study in animals also presents evidence for increased susceptibility to Streptococcus zooepidomicus (Aran d et al. 1986). Immune system effects observed in mice exposed orally to trichloroethylene included inhibition of cell-mediated immunity, delayed type hypersensitivity, and inhibition of antibody-mediated immunity (Sanders et al. 1982). Female mice appeared to be more sensitive than male mice. A study in which a susceptible strain of mice was treated with intraperitoneal injections of trichloroethylene suggests that trichloroethylene can accelerate the autoimmune response (Khan et al. 1995). The immune system may be a sensitive end point for toxic effects from low-level exposure to trichloroethylene however, no firm conclusions can be drawn from the available information. Additional human and animal studies are needed to better characterize this end point and determine the potential for immunological effects for people exposed to trichloroethylene at hazardous waste sites. 

Interferon-7 was the first secretory product of T cells to be discovered when it was found that supernatants derived from suspensions of T cells that had been treated with mitogenic agents could activate macrophages. This macrophage activating factor , subsequently found to interfere with the replication of viruses, was thus named interferon. The production of this compound, associated with delayed-type hypersensitivity and cell-mediated immunity, was termed immune interferon or type II interferon. With the discovery of other lymphokines with interferon-like activity (interferon-a and -j3), the compound was finally designated interferon-7. 

Goetzl, E.J., Voice, J.K., Shen, S. et al. 2001. Enhanced delayed-type hypersensitivity and diminished immediate-type hypersensitivity in mice lacking the inducible VPAC2 receptor for vasoactive intestinal peptide. Proc Natl Acad Sci USA 98 13854-13859. 

The immunocytes are all involved in specific types of immune response that are generally divided into two types (1) cell-mediated, i.e., specifically sensitized T cells (derived from the thymus) which are associated with graft rejection, resistance to certain viruses, bacteria, fungi, and protozoa, and delayed-type hypersensitivity and (2) humoral-mediated, i.e., B cells (bursa equivalent) which produce specific antibodies after the body is exposed to a specific antigen. 

Preclinical studies have shown that impaired immune function determined using a variety of assays, e.g., the plaque-forming cell (PFC) assay, lymphocyte proliferation, delayed-type hypersensitivity, and NK cell activity, is associated with decreased resistance toward experimental infections (Luster et al., 1994). When a drug candidate has been shown to impair immune function in animal studies, the question arises whether similarly negative effects can also be seen in treated human subjects. 

Since rheumatoid arthritis is associated with a disturbance in the immune response as well as an increase in inflammation, the 2-phenyl analogue of rohitukine (8) was also tested in various models associated with immunomodulation [13]. 35% inhibition of oxazolone-induced delayed-type hypersensitivity and 27% inhibition of plaque-forming cells were achieved with a dose of 5.0mg/kg in rats but no effect was observed on... 

In mice with cyclophosphamide-induced immunosuppression, oral administration of 50 to 800 mg/kg methanol extract of curculigo daily for 13 days produced dose-depen-dent increases in humoral antibody titer, delayed-type hypersensitivity, and levels of white blood cells (Bafna and Mishra 2006). 

Toxicology Exposure is through skin absorption. ZDC are skin-contact allergens that can cause type IV delayed type hypersensitivities, and are mutagenic. 

Chase MW (1966) Delayed type hypersensitivity and the immunology of Hodgkin s disease, with a parallel examination of sarcoidosis. Cancer Res 26 1097 Cluff LE, Johnson JE (1964) Drug fever. Prog Allergy 8 149... 

Tamura S, Hatori E, Tsuruhara T et al. Suppression of delayed-type hypersensitivity and IgE antibody responses to ovalbumin by intranasal administration of Escherichia coli heat-labile enterotoxin B subunit-conjugated ovalbumin. Vaccine 1997 15(2) 225-229. 

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