Effects of monoclonal antibodies directed at cell surface molecules on murine experimental autoimmune uveoretinitis

Suppression of established experimental autoimmune uveitis by anti-LFA-1alpha Ab

PURPOSE

To identify costimulatory molecules that are important in the effector phase of experimental autoimmune uveitis (EAU).

METHODS

EAU was induced in C57BL/6 (B6) mice by transfer of activated T cells specific for the interphotoreceptor-binding protein (IRBP) 1-20 peptide. The animals were then treated with and without anti-leukocyte function associated antigen (LFA)-1alpha mAb, at day 0 or 10 (disease onset) after T-cell transfer. Clinical signs of inflammation, ocular histology, and infiltrated inflammatory cells in the eye were compared. The primary and secondary proliferative responses of uveitogenic CD4 and CD8 T cells were tested after treatment with costimulatory blockers in vivo and in vitro. Moreover, the abilities of uveitogenic T cell trafficking and their interaction with retinal astrocytes were examined.

RESULTS

Anti-LFA-1alpha Abs caused significant suppression of disease when administered either at the time of effector uveitogenic T cell transfer or at disease onset. Studies of the mechanisms by which anti-LFA-1alpha Ab inhibits the effector phase of uveitis demonstrated that it blocks multiple pathogenic events of uveitis mediated by IRBP-specific uveitogenic T cells, including the activation of T cells outside and inside the eye and the trafficking of activated autoreactive T cells into the inflammatory site. In addition, Ab treatment selectively suppressed the activation and expansion of pathogenic, but not regulatory, T cells in vivo.

CONCLUSIONS

Anti-LFA-1alpha Abs are potent inhibitors of established autoimmune uveitis and that such treatment may be applicable not only for the prevention, but also the treatment, of T-cell-mediated autoimmune diseases.

Non-myeloablative transplants for congenital diseases

The morbidity and mortality associated with postnatal HSCT, toxicity of HSCT conditioning regimens, lifelong immunosuppressive therapy, and lack of compatible donors discourages many patients and physicians from utilizing postnatal HSCT as a treatment for congenital disease. Non-myeloblative in utero HSCT is now being considered as an alternate treatment with the hope that it will be more therapeutic with less toxicity to a wider spectrum of patients with congenital disorders. Prenatal stem cell transfer may eliminate many of the risks and hazards associated with postnatal HSCT, as the fetus may be less reactive than an immunologically mature individual such that tolerance to donor cells could be developed. GVHD and rejection of postnatal therapeutic grafts may be minimized thus reducing or eliminating altogether the need for postnatal myeloablation and immunosuppression. Much work must be done both in animal studies as well as in clinical trials. By using well-designed murine models such as the beta-thalassemic mouse outlined above, we believe we can determine the optimal conditions for non-myeloablative postnatal transplants with allogeneic or haplocompatible HSC following prenatal tolerance induction with these cells. In addition, we may answer basic immunology questions regarding the development and regulation of immunity and tolerance in both mice and humans.

ICAM-1 expression on the surface of T lymphocytes in patients with uveitis: a comparative study between the eye and peripheral blood

PURPOSE

We studied the surface expression of intracellular adhesion molecule 1 (ICAM-1) on peripheral and intra-ocular T lymphocytes in patients with active uveitis.

METHODS

Two-colour flow-cytometric analysis was performed on cells isolated from aqueous humour and peripheral blood of 23 patients with active uveitis and 16 control patients who were to undergo cataract extraction, in order to determine the percentage of cells expressing CD4, CD8 and ICAM-1 (CD54) molecules.

RESULTS

In the aqueous humour of patients with uveitis, we found an increase in the percentage of CD4+ and CD8+ lymphocytes, co-expressing the ICAM-1 molecule as compared to control patients (p < 0.0001). In peripheral blood, these uveitis patients exhibited a significant decrease in the percentage of CD4+ICAM-1+ (p = 0.0106) and CD8+ICAM-1+ (p = 0.0014) as compared to control subjects. The comparative study of cells from the aqueous humour and peripheral blood showed that the percentage of CD4+ICAM-1+ cells was higher in the aqueous humour (p < 0.0001). Comparison of the aqueous humour and peripheral blood for CD8+ICAM-1+ cells revealed no significant differences. In addition, we found a high negative correlation for the CD8+ICAM-1+ subset between the aqueous humour and peripheral blood.

CONCLUSIONS

Our results suggest a greater local participation for CD4+ICAM-1+ cells but not for CD8+ICAM-1+ cells in the pathogenesis of uveitis.