Ao Strain Research Articles

Evidence for target tissue regulation of resistance to the induction of experimental allergic encephalomyelitis in AO rats

A myelin basic protein (MBP)-specific T cell line derived from F1 hybrids between experimental allergic encephalomyelitis (EAE)-susceptible DA (RT1 av1) strain and EAE-resistant AO (RT1 u) strain was capable of inducing clinical EAE in F1 hybrids and DA, but not in AO rats. In vitro restimulation with MBP presented by AO antigen-presenting cells (APC) resulted in the generation of a MBP-specific subline restricted by RT1 u MHC products which induced clinical EAE in F1 hybrids but not in the AO parental strain. Deletion of hosts' leukocytes using sublethal irradiation and cytotoxic drugs did not abrogate the resistance of AO rats, which argues against the involvement of hosts' lymphoid cells in the regulation of autoagression. Thus, mechanism(s) regulating the activity of autoagressive T cells on functional elements in the target tissue might be responsible for differences in susceptibility to EAE.

Adjuvant properties of polysaccharides: Effect of iota‐carrageenan, pectic acid, pectin, dextran and dextran sulphate on the humoral immune response in the rat

Iota-carrageenan can both enhance agglutinating antibody responses and trigger reaginic antibody production against a protein associated antigen in rats. The present study investigates the strain specificity of this phenomenon and compares the adjuvanticity of high and low molecular weight iota-carrageenan with a series of structurally distinct polysaccharides (pectin, pectic acid, dextran and dextran sulphate). Using ovalbumin as the test antigen, high molecular weight iota-carrageenan induced a potent ovalbumin specific reaginic antibody response in PVG and Hooded Lister strain rats, an intermediate response in Sprague Dawley rats and a weak response in DA, AO and F344 strain rats. Further studies in PVG rats revealed that the nature and magnitude of the antibody response induced was influenced by the type of polysaccharide carrier used. Thus, whereas, high molecular weight carrageenan enhanced the agglutinating antibody (agglutinin) response and simultaneously elicited de novo reaginic antibody production to co-administered ovalbumin, low molecular weight carrageenan facilitated reaginic antibody production but had no effect on the agglutinin response. Pectin and dextran had no effect on the agglutinin response and failed to elicit reaginic antibody production. Conversely, pectic acid and dextran sulphate enhanced the agglutinin response and elicited a transient reaginic anti-ovalbumin response.

Correlation of IL2 production and lymphoid tissue make-up in two inbred strains of rats.

Strain differences in susceptibility to the experimentally induced autoimmunity provide valuable tools for analysing and understanding cellular and genetic deffects leading to autoimmunity in humans. We have shoun that AO and DA inbred strains of rats differ in susceptibility to the induction of several experimental T cell dependent autoimmune diseases, the former being resistant and latter susceptible to these disorders. In search for the cellular basis of the observed differences and in view of the central role played by Interleukin 2 (IL2) in regulating T cell response,we have analysed the pattern of IL2 production in DA and AO strain and found striking difference between these tuo strains (1).Supernatants obtained from ConA stimulated AO lymphocytes revealed louer IL2 activity when compared with preparations derived from DA cells (1). It appeared that a gene not linked to the MHC exerts the major control on the level of IL2 production in this strain combination (2).KeywordsLymphoid TissueCell SubsetInbred StrainStrain DifferenceCellular BasisThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.