Parasitic worms and inflammatory diseases.

The debate on whether infection precipitates or prevents autoimmunity remains a contentious one. Recently the suggestion that some unknown microbe can be at the origin of some chronic inflammatory diseases has been countered by accumulating evidence that decreasing infection rates might have an important role to play in the rising prevalence of autoimmune disorders. The 'Hygiene Hypothesis' was initially postulated to explain the inverse correlation between the incidence of infections and the rise of allergic diseases, particularly in the developed world. Latterly, the Hygiene Hypothesis has been extended to also incorporate autoimmune diseases in general. Amongst the various infectious agents, a particular emphasis has been put on the interaction between parasitic worms and humans. Worm parasites have co-evolved with the mammalian immune system for many millions of years and during this time, they have developed extremely effective strategies to modulate and evade host defences and so maintain their evolutionary fitness. It is therefore reasonable to conclude that the human immune system has been shaped by its relationship with parasitic worms and this may be a necessary requirement for maintaining our immunological health. Fully understanding this relationship may lead to novel and effective treatments for a host of deleterious inflammatory reactions.

Effect of X- and Y-box deletions on the development of diabetes in H-2Ealpha-chain transgenic nonobese diabetic mice.

The development of type 1 diabetes in nonobese diabetic (NOD) mice is influenced by major histocompatibility complex (MHC) class II genes. The NOD-E transgenic mouse, which expresses H2-E as a result of the introduction of an Ead gene, is protected from development of type 1 diabetes. While the mechanism of protection remains unclear, the effect has been regarded as a model system for MHC protection from autoimmunity. We have investigated the effect of deletions of the Ea promoter region, which, in turn, affect H2-E expression patterns in transgenic NOD mice. We have constructed transgenic NOD mice where the X (DeltaX) and Y (DeltaY) boxes of the Ead gene have, respectively, been functionally deleted. Previous reports, using X- or Y-box-deleted H2-E transgenic mice, made by crossing the appropriate transgenes onto the NOD background from C57BL/6 transgenic mice, indicated that promoter mutation abrogated the H2-E-mediated protection seen in NOD-E. The NOD DeltaX and NOD DeltaY transgenic mice generated in the present study differ in susceptibility to diabetes from wild-type NOD mice. NOD DeltaY1 animals are protected from diabetes development, while DeltaX mice remain susceptible, albeit to a lesser extent than the parental NOD strain.

Unraveling immunology.

A report on the 11th International Congress of Immunology, Stockholm, Sweden, 22-27 July 2001.

Nondepleting anti-CD4 has an immediate action on diabetogenic effector cells, halting their destruction of pancreatic beta cells.

The induction of tolerance in a primed immune system is a major aim for therapy in autoimmunity and transplant rejection. In this paper, we investigate the action of the nondepleting anti-CD4 Ab, YTS 177. Although this Ab is nondepleting, we have demonstrated a direct action in vivo on activated effector cells. We show that the Ab inhibits transfer of insulin-dependent diabetes mellitus by the CD4+ Th1 clone BDC2.5 to nonobese diabetic mice. Furthermore, we show that this Ab acts directly on diabetogenic effector cells because it prevented BDC2.5-induced insulin-dependent diabetes mellitus in nonobese diabetic-scid recipients in the absence of other T cells. The Ab halts the diabetic process even when it is administered after the BDC2.5 cells have infiltrated the pancreas and destruction of islets is already underway. This is accompanied by an immediate decrease in proinflammatory cytokine production with cessation of beta cell destruction and disappearance of infiltrating cells from the pancreas, leaving any remaining beta cells intact. These data suggest that Abs such as this may be effective not only because they induce regulatory T cells but also because they are able to directly prevent effector cell function.

Gene transfer to ex vivo stored corneas.

PURPOSE: We examined the efficiency and kinetics of recombinant adenovirus vector-mediated gene transfer to rat and rabbit cornea in culture ex vivo. METHODS: A recombinant replication-defective adenovirus was used to transfer a lacZ marker gene to whole rat and rabbit corneas in culture. Histochemistry was used to localise transgene expression and a colorimetric assay to quantify recombinant protein expression. RESULTS: After infection with recombinant virus and culture for 3 days, high-efficiency gene transfer was found, with expression in most endothelial cells of both species. Minimal expression was found in other corneal cell types. On histochemistry, longer duration of expression was found in rat than in rabbit endothelium. In both rat and rabbit cornea, highest levels of recombinant protein were found at days 3-7 after incubation with virus, decreasing to low or undetectable levels at 21 days. CONCLUSION: Adenovirus vectors allow high-efficiency transgene expression in cornea, largely restricted to the endothelial cells of ex vivo cultured cornea. Kinetics of expression differ according to the species of cornea studied, a factor that must be considered if this vector is used in further studies.

Ex vivo adenovirus-mediated gene transfer and immunomodulatory protein production in human cornea.

One attractive strategy to prevent or control allograft rejection is to genetically modify the donor tissue before transplantation. In this study, we have examined the feasibility of gene transfer to human corneal endothelium, using a number of recombinant adenovirus constructs. Ex vivo infection of human corneas with adenoviral vectors containing lacZ, under transcriptional control of either cytomegalovirus (CMV) or Rous sarcoma virus (RSV) promoters, provided high-level gene expression, which was largely restricted to endothelium. Expression of the reporter gene persisted at relatively high levels for up to 7 days, followed by a decline to indetectable levels by 28 days. RT-PCR analysis of lacZ transcription showed a similar picture with a short period (3-7 days) of RNA transcription after infection. In contrast, adenoviral DNA persisted for at least 56 days. Subsequently, we examined the expression of a potential therapeutic gene, CTLA-4 Ig fusion protein. Following infection of human corneas with adenoviral vectors encoding CTLA-4 Ig protein, high levels of the fusion protein were detected in corneal culture supernatants for up to 28 days. This protein was functionally active, as determined by binding to B7.1 (CD80)-expressing transfectants. This study suggests that genetic alteration of donor cornea before transplantation is a feasible approach for preventing or controlling allograft rejection. Similar gene-based strategies might also be feasible to prevent rejection of other transplanted tissues or organs.