Responses cell mediated

The theoretieal baekground whieh underlies immunity to infection has been discussed in detail in Chapter 14. Immunity to infeetion may be passively acquired through the receipt of preformed, proteetive antibodies or it may be aetively acquired through an immune response following deliberate or accidental exposure to microorganisms or their eomponent parts. Aetive aequired immunity might involve either or both humoral and cell-mediated responses. 

Macrophage (peritoneal, pleural, alveolar spaces) Histiocytes (tissues) Monocytes (blood) some cell-mediated responses)... 

Figure 7.1 Cellular processes of the immune response. A simplified summary of the sequence of events in both the humoral and cell-mediated response to an antigen.

Cell-mediated response to substances results in the formation of scar tissue in the supporting tissue of the lung... 

The mode of association of peptides to liposome carriers might also be critical to induce a preferential immune response either humoral or cell mediated. For example, using a human mucin MUCl 20-mer peptide, it was found that only the physical association of the peptide to liposomes (either encapsulated or surface exposed after anchoring) was necessary to observe a cell-mediated response (34). In line with this observation, it was recently shown that a soluble peptide, representing a Melan-A/MART-1 tumor-associated antigen, when encapsulated into sterically stabilized liposomes, was able to stimulate a CTL response and this construct represented a suitable formulation for a specific tumor immunotherapy (69). In contrast, and in agreement with other studies (16), only the liposome surface exposed... 

The appearance of any such cancer-associated antigen should thus be capable of inducing an immune response which, if successful, should eradicate the transformed cells. The exact elements of immunity responsible for destruction of transformed cells remain to be fully characterized. Both a humoral and cell-mediated response can be induced, although the T cell response appears to be the most significant. 

Most vaccine vectors developed to date are viral-based, with poxviruses, picornaviruses and adenoviruses being used most. In general, such recombinant viral vectors elicit both strong humoral and cell-mediated immunity. The immunological response (particularly the cell-mediated response) to subunit vaccines is often less pronounced. 

Very often whole-killed vaccines are formulated with adjuvants, which are designed to enhance vaccine persistence and induction of immune responses. However, the only adjuvant currently approved by FDA for clinical use is alum, in the form of vaccines complexed with aluminum hydroxide or aluminum sulfate. Even with the help of alum adjuvants, inactivated vaccine antigens are presented to APC extracellularly, as opposed to intracellularly, leading to a bias toward antibody-mediated responses. Little or no cell-mediated response to whole-killed vaccines with alum adjuvant renders some vaccines ineffective. 

The materials capable of stimulating the lymphoid tissues to produce antibodies are termed antigens and comprise bacterial and viruses as well as some smaller molecular entities. However, the response is not to the intact organisms but rather to some specific parts which have characteristic three-dimensional structures, the epitopes, and this sensitivity to structure is a characteristic feature of the immune response. Once an animal is in contact with an epitope the response can be in the circulatory or humoral system or directly as a cell-mediated response, but it is exquisitely sensitive to the specific antigen and rarely to any other. 

The Complement System Facilitates Removal of Microorganisms and Antigen-Antibody Complexes The Cell-Mediated Response A Separate Response by T Cells... 

The Cell-Mediated Response 4 Separate Response by T Cells... 

Cyclophosphamide disturbs the mechanisms associated with DNA synthesis and cell proliferation by alkylating DNA in proliferating and nonproliferating cells. Its mechanisms of immunosuppressive effects are similar to its antineoplastic actions. Cyclophosphamide affects both B and T cells, but it produces more toxicity to B cells because they recover slowly. It has some unpredictable effects on T-cell-mediated immunity where it actually augments some T-cell-mediated responses however, the overall response is inhibitory. 

Hui, G.S., Hashimoto, C.N. Adjuvant formulations possess differing efficacy in the potentiation of antibody and cell mediated responses to a human malaria vaccine under selective immune genes knockout environment. Int Immunopharm 8 (2008) 1012-1022. 

Evaluating the immune response to the vaccine at the same time as evaluating toxicity is recommended in a 2003 WHO guideline (Table 31.1). This makes good sense because any toxicity observed with vaccines is frequently related to the immune response, and correlation of these two endpoints provides a fuller explanation of the test results. Assays to measure the immune response include those which measure antigen-specific antibody responses (e.g., ELISA) and cell-mediated responses (e.g., y-interferon—ELISPOT). Developing these... 

As noted previously, Zn has an important role in numerous critical biochemical processes, including immunity. In addition to the positive effects of Zn supplementation, various antioxidant vitamins have been shown to stimulate the immune system. Thus, supplementation of elderly individuals with a combination of vitamins A, C, and E showed significant improvement in the following cell-mediated responses (P12) (a) increased total number of circulating T-cells (b) increased the number of helper (CD4+) T-cells (c) increased helper-to-cytotoxic cell ratio (CD4+ to CD8+) and (d) increased total number of lymphocytes in response to phytohemagglutinin. Others (M12), in a double-blind, placebo-controlled study of an elderly group supplemented with vitamin E, demonstrated (a) increased... 

The pathogenesis of atopic dermatitis remains unclear, although there appears to be a relation to IgE, along with a genetic influence. Although investigators have focused on a dysfunctional immune system, there is no conclusive evidence to support the assumption that cell-mediated response occurs in atopic dermatitis. Elevated serum IgE levels may be found. 

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