Lactobacilli as antigen delivery system for mucosal tolerance induction in autoimmune disease

Multiple sclerosis (MS) is a chronic inflammatory disease of the central nervous system (eNS) that affects eNS myelin which isolates nerve axons and allows saltatory pulse conduction. It is the most important chronic disabling neurological disease in young adults, with a mean age of onset around 30 years. It has a prevalence of approximately I per 1000 in Western European countries and it affects women versus men at a ratio of 1.5 to I (Sadovnick and Ebers, 1993). Although the cause and pathogenesis of MS are unknown, it is generally believed that MS is an autoimmune disease in which environmental factors as well as genetic factors are involved. Studies with monozygotic twins reveal an MS concordance rate of 20-30%, ·whereas this is 3-5% for dizygotic twins (reviewed by Ebers and Sadovnick, 1994). This high concordance rate is a strong argument in favor of a genetic basis of MS, but can also be used as an argument for an environmental involvement in MS. The role of environmental factors in MS is supported by the presence of geographic gradients in the distribution of the disease. The general pattern is that MS prevalence rises with increasing distance from the equator. The nature of these environmental factors is unknown. Dietary factors, climate variation and infectious agents have all been postulated to be involved in MS, but there is no definitive proof for involvement in MS of any of these factors. Especially herpes viruses have gained interest the last few years (Dalgleish, 1997). The notion that MS is a multifactorial disease is strengthened by the fact that the clinical course of MS is highly variable for each individual patient, and can be divided into four categories (Lublin and Reingold, 1996). The first category is relapsingremitting disease, in which discrete attacks are alternated with periods in which a patient returns to the pre-attack base line. In the relapsing-progressive form of MS, the patients do not return to base-line level in between attacks and disability increases in these patients. In chronic-progressive disease, the disease progresses without periods of stability. The uncommon fourth form is characterized by a progressive relapsing course of MS

Growth phase of orally administered Lactobacillus strains differentially affects IgG1/IgG2a ratio for soluble antigens: Implications for vaccine development

Lactobacillus strains with probiotic activity are major constituents of numerous common food products. Due to their 'generally regarded as safe'-status (GRAS-status), Lactobacillus strains can also be genetically engineered for use in oral immunotherapeutic applications, such as vaccination and T lymphocyte tolerance induction in autoimmune disease. In the current study, we demonstrate that the growth phase of orally administered individual Lactobacillus strains can differentially affect antigen-specific antibody subclasses IgG1 and IgG2a, which might reflect skewing of systemic activity of T helper cell type 2 (Th2) and T helper cell type 1 (Th1) pathways, respectively. Mice were orally fed different wild type Lactobacillus strains in log phase or stationary phase and immunized intraperitoneally with a T-cell dependent protein antigen. Sera were evaluated for the ratio of antigen-specific IgG1 and IgG2a antibodies. Stationary Lactobacillus murines and Lactobacillus casei cultures, but not two other Lactobacillus strains, evoked significantly higher IgG1/IgG2a ratios than log phase cultures, possibly relating to increased activity of the Th2-pathway. Despite normal variation in antibody responses against TNP-CGG among individual mice, a high correlation was found between the IgG1 and IgG2a responses of mice within experimental groups. This differential antibody response is likely due to growth phase-dependent differences in bacterial cell composition. Since Lactobacillus growth phase dependent skewing of antibody responses possibly reflecting T-cell pathways can inadvertently affect allergic and (auto)-immune responses, the current findings strongly caution against unidimensional views on the oral administration of individual Lactobacillus strains for probiotic or immunotherapeutic purposes, but also suggest additional possibilities for immune modulation

Reduced experimental autoimmune encephalomyelitis after intranasal and oral administration of recombinant lactobacilli expressing myelin antigen

Oral administration of autoantigens is a safe and convenient way to induce peripheral T-cell tolerance in autoimmune diseases like multiple sclerosis (MS). To increase the efficacy of oral tolerance induction and obviate the need for large-scale purification of human myelin proteins, we use genetically modified lactobacilli expressing myelin antigens. A panel of recombinant lactobacilli was constructed producing myelin proteins and peptides, including human and guinea pig myelin basic protein (MBP) and proteolipid protein peptide 139-151 (PLP139-151). In this study we examined whether these Lactobacillus recombinants are able to induce oral and intranasal tolerance in an animal model for multiple sclerosis, experimental autoimmune encephalomyelitis (EAE). Lewis rats received soluble cell extracts of Lactobacillus transformants intranasally three times prior to induction of EAE. For the induction of oral tolerance, rats were fed live transformed lactobacilli for 20 days. Ten days after the first oral administration EAE was induced. Intranasal administration of extracts containing guinea pig MBP (gpMBP) or MBP72-85 significantly inhibited EAE in Lewis rats. Extracts of control transformants did not reduce EAE. Live lactobacilli expressing guinea pig MBP72-85 fused to the marker enzyme β-glucuronidase (β-gluc) were also able to significantly reduce disease when administered orally. In conclusion, these experiments provide proof of principle that lactobacilli expressing myelin antigens reduce EAE after mucosal (intranasal and oral) administration. This novel method of mucosal tolerance induction by mucosal administration of recombinant lactobacilli expressing relevant autoantigens could find applications in autoimmune disease in general, such as multiple sclerosis, rheumatoid arthritis and uveitis