T-cell-targeted immunotherapy

The cytokines NAP-1 (IL-8), MCP-1, IL-1 beta, and GRO in rabbit inflammatory skin lesions produced by the chemical irritant sulfur mustard

Developing and healing dermal inflammatory lesions were produced in rabbits by the topical application of dilute sulfur mustard (SM), the military vesicant. In tissue sections of such lesions, cells containing the mRNA of important cytokines were identified with in situ hybridization techniques. These cytokines were neutrophil attractant/activation protein-1 (NAP-1 (also called IL-8), monocyte chemoattractant (activating) protein 1 (MCP-1), interleukin 1 (beta) (IL-1 (beta)), and GRO (a growth factor and chemokine). Mononuclear cells (mainly macrophages and activated fibroblasts) contained the mRNA of all four of these cytokines. A higher percentage of cytokine-producing mononuclear cells (macrophages and activated fibroblasts) was present in lesions at 2 days (their peak size) than at 6 days, when they were almost healed. Granulocytes emigrated from the bloodstream, passed through the lesions, and were the major constituent of the protective crust. This sequence correlated with the distribution of cells able to produce NAP-1: At 2 days and 6 days, the mononuclears that contained messenger RNA for this granulocyte chemoattractant were found mainly in the upper part of the dermis. At 2 days and 6 days, cells containing the mRNA of IL-1, a primary cytokine, were also found predominantly in the upper dermis, i.e., nearest the site of injury. In contrast, mononuclears containing the mRNA of MCP-1 (a monocyte chemoattractant), and the mRNA of GRO (a granulocyte chemoattractant) were more equally distributed throughout the dermis. SM stimulated hair follicle epithelial cells to up-regulate GRO mRNA and, to a lesser degree, NAP-1 mRNA. Apparently, the irritation produced by SM directly or indirectly induces such epithelial cells to manufacture these growth factors. In the rabbit, hair follicles are known to be the main source of new epithelial cells after the covering epithelium has been destroyed. Therefore, GRO is probably a major autocrine-paracrine stimulus for such repair. A brief review of the role of cytokines in dermal inflammation is presented.

Antigenic mimicry of natural L-peptides with retro-inverso-peptidomimetics

Three analogues of the model peptide of sequence IRGERA corresponding to the COOH-terminal residues 130-135 of histone H3 were synthesized, and their antigenicity, immunogenicity, and resistance to trypsin were compared to those of the natural L-peptide. The three analogues correspond to the D-enantiomer, containing only D-residues, and two retro-peptides containing NH-CO bonds instead of natural peptide bonds. The chirality of each residue was maintained in the retro-peptide and inverted in the retro-inverso-peptide. Antibodies to the four peptide analogues were produced by injecting BALB/c mice with peptides covalently coupled to small unilamellar liposomes containing monophosphoryl lipid A. Each of the four peptide analogues induced IgG antibodies of various subclasses. The IgG3 antibodies reacted similarly with the four analogues, whereas antibodies of the IgG1, IgG2a, and IgG2b isotypes showed strong conformational preferences for certain peptides. The retro-inverso-peptide IRGERA mimicked the structure and antigenic activity of the natural L-peptide but not of the D- and retro-peptides, whereas the retro-peptide IRGERA mimicked the D-peptide but not the L- and retro-inverso-peptides. The equilibrium affinity constants (Ka) of three monoclonal antibodies generated against the L- and D-peptides with respect to the four peptide analogues were measured in a biosensor system. Large differences in Ka values were observed when each monoclonal antibody was tested with respect to the four peptides. The use of retro-inverso-peptides to replace natural L-peptides is likely to find many applications in immunodiagnosis and as potential synthetic vaccines.

Prevention strategies for multiple sclerosis

The design of effective prevention strategies for multiple sclerosis (MS) is hampered by ignorance of the basic pathophysiology of the disease. An understanding of specific immune mechanisms, the nature of genetic susceptibility, and environmental triggers will permit rational decision making from among the many proposed therapeutic directions available. It is reasonable to hypothesize that inhibition of central nervous system inflammation will be of benefit in MS, regardless of the trigger (autoantigen, exogenous antigen, or nonspecific trigger). Emerging concepts are reviewed to provide guideposts for the design of rational therapy for MS.

Immunological studies on type 1 diabetes in identical twins

Diabetes is a multifactorial disease, the pathogenesis of which involves participation of the host immune system in beta cell destruction. Studies on identical twins offer the opportunity to define genetic and non-genetic factors which may contribute to susceptibility to the disease. Our own work indicates that the number and nature, as well as the intensity and persistence of immune abnormalities of cellular and humoral immune responses can be powerful predictors of the disease and also identify twins who have a degree of protection from the disease.

Is there a role for gamma delta T cells in malaria?

Peripheral blood lymphocytes of the V gamma 9+ family of gamma delta T cells proliferate vigorously in response to Plasmodium falciparum. In this brief article, Jean Langhorne and colleagues discuss this response and assess the possible role of gamma delta T cells in the pathogenesis of malaria.