Immunological responses

Primary skin irritation is the immediate result of the contact of a substance with skin. Symptoms appear only in the area of contact and generally correspond to local erythema and sometimes to edema and vesiculation but they commonly disappear in several hours. When there is a specific immunological response to the substance in contact with the skin, the substance is said to be a sensitizer. Subsequent responses to the contact of the skin with small amounts of this substance will probably cover large areas of the body and are not limited to erythema and edema but also to itching, suppuration, and a long persistence of the reaction. 

In addition, silicone polymers in both gel and elastomer forms have been shown to induce a typical subcutaneous foreign body reaction and fibro sarcoma development in rats. The lower-molecular weight silicone polymers may migrate into the adjacent tissues or stimulate other cellular and immunological response. 

The same polymer was later shown to possess striking immunoadjuvant features [403,664-670], i.e. to be able to enhance the immunologic response of the body to the stimulus of an antigen. 

Many microorganisms minimize the effects of the host s defence system against them by mimicking the antigenic stmcture of the host tissne. The eventual immunological response of the host to infection then leads to the autoimmune destmction of itself. Thus, infections with Mycoplasma pneumoniae can lead to production of antibody against normal Group 0 erythrocytes with concomitant haemolytic anaemia. 

Pain at the injection site is one of the most commonly reported adverse effects of vaccination. The reaction is usually mild with complaints of pain and tenderness at the injection site that may or may not be accompanied by erythema. Local reactions tend to be more frequent with repeated doses or booster doses of vaccine. The frequency and degree of the reactions appear to be related to the amount of preformed antibodies and rapid immunologic responses reflective of priming from previous doses. More serious Arthus reactions are infrequently reported. Arthus reactions are classified as type III hypersensitivity reactions, and are characterized by a massive local response involving the entire thigh or deltoid. Arthus reactions are also related to preformed antibody complexes that induce an inflammatory lesion.14... 

The success of antiretroviral therapy is measured by the degree to which the therapy (1) restores and preserves immunologic function, (2) maximally and durably suppresses HIV RNA, (3) improves quality of life, and (4) reduces HIV-related morbidity and mortality. The major outcome parameters are CD4+ lymphocyte absolute count and percentage, and plasma HIV RNA. Adequate immunologic response in antiretroviral-naive patients consists of an increase in CD4+ cell count that averages 100 to 150 cells/mm3 per year (with a faster response in the first 3 months), and a 1 log decrease in HIV RNA by 2 to 8 weeks after starting... 

Pritchard, D.I., Hewitt, C. and Moqbel, R. (1997) The relationship between immunological responsiveness controlled by T helper 2 lymphocytes and infections with parasitic helminths. Parasitology S33-S44. 

Bacterial polysaccharides were first recognized nearly one hundred years ago, but information about their structures and properties has been obtained almost entirely during the last fifteen or twenty years. Combined with protein, these polysaccharides are responsible for the immunizing powers of many bacteria, and the structure of the polysaccharide determines the exact or specific immunological response to these organisms. 

From Figure 9 it can be concluded that the sensitivity of the assay is adequate to screen water samples for the presence of atrazine at a MAC value of 0.1 ppb. In a preliminary experiment 10 river water samples were screened for the presence of atrazine. In eight out of 10 an immunological response corresponding to atrazine levels greater than 0.1 ppb could be confirmed by GC-MS analysis. The other two samples contained atrazine at levels below 0.1 ppb (both with the enzyme immunoassay as with the GC-MS analysis). 

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