Mediated Immunity

The association of any one HLA type with ALS is controversial. Initial studies found no statistical association with ALS, however increased incidences of ALS patients that express HLA-A3, -Bw40, -Bw35, -B18, -Cw4, as well as decreased incidence of HLA-A9, -B8, -B7, and -DR4 were discovered. Additionally, milder disease progression is associated with HLA-A12 and -Bw40, whereas more aggressive disease is associated with HLA-Bw35. 

In ALS patients, lymphocytes, as well as myeloid cells are consistently found within or around affected tissues (Graves et al., 2004). Affected tissues with lymphocytic infiltrates include spinal cords, brain, muscles, and associated vessels (Graves et al., 2004). Most reports have identified the infiltrating lymphocytes as T cells, with a minor presence of B cells. Most indicate that both CD4 and CD8+ T cells are present 

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Pneumogstis carini pneumonia (PCP), the most common of the opportunistic infections, occurs in more than 80% of AIDS patients (13). Toxoplasmosis, a proto2oan infection of the central nervous system, is activated in AIDS patients when the 004 count drops and severe impairment of ceU-mediated immunity occurs. Typically, patients have a mass lesion(s) in the brain. These mass lesions usually respond well to therapy and can disappear completely. Fungal infections, such as CTyptococcalmeningitis, are extremely common in AIDS patients, and Histop/asma capsulatum appears when ceU-mediated immunity has been destroyed by the HIV vims, leading to widespread infection of the lungs, Hver, spleen, lymph nodes, and bone marrow. AIDS patients are particularly susceptible to bacteremia caused by nontyphoidal strains of Salmonella. Bacteremia may be cleared by using antibiotic therapy. 

Chemical-mediated immune suppression has been identified from the experimental study of several wildlife species. Harbour seals fed either chemically contaminated fish from the Wadden Sea or imcontaminated fish were found to have differing immune responses, with the exposed group showing lowered immune response to microbial infections and certain types of cancer. "" Mink fed fish taken from below a discharge point for bleached Kraft pulp mill effluent have also shown impaired immune function, " showing that the non-accnmillative chemicals in this effluent can actively disrupt endocrine associated functions. 

Birds. In avian populations, organochlorine-associated suppression of T-cell mediated immune response has been found in herring gull and Caspian tern colonies adjacent to the Great Lakes in Northern America.In the most severe cases, immune response was suppressed by up to 50%. Similarly, seabirds exposed to petrochemicals from oil spills have been found to have suppressed immune function. " ... 

A mechanism of cell-mediated immunity whereby an effector cell of the immune system actively lyses a target cell that has been bound by specific antibodies. The typical ADCC involves activation of natural killer (NR) cells and is dependent on the recognition of... 

Cell-mediated immunity (CMI) is the result of the activity of many leukocyte actions, reactions, and interactions that range from simple to complex. This type of immunity is dependent on the actions of the T lymphocytes, which are responsible for a delayed type of immune response The T lymphocyte becomes sensitized... 

The intermediate-duration oral MRL was derived based on the observation of decreases in humoral and cell-mediated immune responses in rats consuming 0.9 mg/kg/day for 22 weeks (Banerjee and Hussain 1986). Choice of this end point is supported by the observation of similar effects in rats at higher doses following ingestion for shorter periods (Banerjee and Hussain 1986, 1987) and decreased neutrophils and... 

Banerjee BD, Hussain QZ. 1986. Effect of sub-chronic endosulfan exposure on humoral and cell-mediated immune responses in albino rats. Arch Toxicol 59 279-284. 

Acne is a common disease affecting almost 100% of youngsters [i, 2]. Acne settles in the vast majority by 20-25 years of age but 1% of males and 5% of females exhibit acne lesions at 40 years of age [3]. Scarring occurs early in the course of acne and may affect, to some degree, 95% of patients from both sexes [4]. Differences in the cell-mediated immune response are involved in the personal tendency to develop post-acne scarring [5]. 

Allison, A. C., and Byars, N. E. (1986). An adjuvant formulation that selectively elicits the formation of antibodies of protective isotypes and of cell-mediated immunity, J. Immunol. Meth.. 95. 157-168. 

Antigens, however, can induce a second type of response which is known as the cell-mediated immune response. The antigenic agent stimulates the appearance of sensitized lymphocytes in the body which confer protection against organisms that have the ability to live and replicate inside the cells of the host. Certain of these lymphocytes are also involved in the rejection of tissue grafts. 

The term cell-mediated immunity is used to describe the localized reactions that occur to those microorganisms that have the ability to live and multiply within the... 

Humoral antibodies of the IgG elass are able to eross the placenta flxm mother to fetus. These antibodies will provide passive proteetion of the new-born against those diseases which involve humoral immunity and to which the mother is immune. In this fashion, new-born infants in the UK have passive proteetion against tetanus but not against tuberculosis which requires cell-mediated immunity. Seeretory antibodies are also passed to the new-born together with the first deliveries of breast milk (colostrum). Such antibodies provide some passive protection against infections of the gastrointestinal tract. 

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. 

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