Stimulating the Immune Response

The use of cytokines in AIDS has already been described in chapter 2. 

---

Live vaccines are normally weakened strains that do not cause diseases in the host, but stiU can stimulate the immune response. A typical example is the poho vaccine. The weakening of microorganisms or attenuation of the vims or bacteria can be accompHshed by passage through different substrates and/or at different temperatures. Modem genetic engineering techniques can also be used to attenuate a vims or bacterium. 

Hydroxymethyl-6-methyluracil (1043) was prepared many years ago from 6-methyl-uracil and formaldehyde, or in other ways. Since 1956 it has received much attention in the USSR under the (transliterated) name pentoxyl or pentoxil. It is used in several anaemic and disease conditions. For example, a mixture of folic acid and pentoxyl quickly reduces the anaemia resulting from lead poisoning pentoxyl stimulates the supply of serum protein after massive blood loss it stimulates wound healing it stimulates the immune response in typhus infection and it potentiates the action of sulfonamides in pneumococcus infections (70MI21300). 

Both vaccines and toxoids are administered to stimulate the immune response within the body to specific antigens or toxins. These agents must be administered before exposure to the pathogenic organism. The initiation of the immune response, in turn, produces resistance to a specific infectious disease. The immunity produced in this manner is active immunity. Display 54-5 gives examples of indications for use of toxoids and vaccines. 

Carrier protein Macromolecule to which a hapten is conjugated, thereby enabling the hapten to stimulate the immune response. catELISA Similar to an ELISA, except that the assay detects catalysis as opposed to simple binding between hapten and antibody. The substrate for a reaction is bound to the surface of the microtitre plate, and putative catalytic antibodies are applied. Any product molecules formed are then detected by the addition of anti-product antibodies, usually in the form of a polyclonal mixture raised in rabbits. The ELISA is then completed in the usual way, with an anti-rabbit second antibody conjugated to an enzyme, and the formation of coloured product upon addition of the substrate for this enzyme. The intensity of this colour is then indicative of the amount of product formed, and thus catalytic antibodies are selected directly. 

Table 18.4 Composition of two parenteral feeds designed to stimulate the immune response...

The importance of these structures is clear by observing the numerous biomedical applications7711 that have been suggested for such compounds including inhibition of viral and bacterial infections, tumor eradication by stimulating the immune response, preventing toxin binding, and many others. Selected examples have been chosen to illustrate these potentialities. 

The systems involved in the defense mechanism of the body are both varied and complex. Investigating the role of biologically active peptides has proved to be a very promising line of research. The main focus is on two peptide groups, namely on immunomodulatory (stimulating the immune response) and antimicrobial (inhibiting pathogenic microbes) peptides. 

The immune system uses self-tolerance to neutralize, destroy, and eliminate any non-self proteins and cells, including microorganisms. Non-self proteins and cells include self-cells (the body s own cells) that have become infected or debilitated (cancer cells). The immune system recognizes self-cells by unique proteins on the surface of self-cells. Foreign cells have different proteins called antigens that stimulate the immune response by the immune system. Immune system cells originate and mature in bone marrow and release into the blood, where immune system cells search for non-self-cells. 

The immune system is able to recognize self-cells by using unique proteins that are on the surface of all self-cells. Think of these proteins as an identification code. Foreign cells have a different identification code. These are called antigens and stimulate the immune response of a host. 

Chitosan has also been shown to possess antiviral activity and it exerts its action by stimulating the immune response of the host system against the viral antigens [31]. 

Particle formation from arthroplasty implants can lead to complications in the post-operative period. It has been shown that wear particles from implants induce a systemic reaction that stimulates an immune response to the implants and joint. This immune reaction brings activated macrophages into the joint that medicate a process of osteolysis and bone resorption from the implants [25], The end product of this devastating complication is implant failure and revision arthroplasty surgery. Ideal implants have minimal to no wear particle formation and therefore would not stimulate the immune response that causes failure. 

---