ABSTRACT
A prophylactic vaccine composed of killed promastigotes of five stocks of Leishmania was tested as an immunotherapeutic agent against American cutaneous leishmaniasis (ACL). The agent was administered by deep intramuscular injection daily for 10 days, followed by a 10-day interval. Out of 62 patients so treated, 47 (76%) were considered clinically cured; 41 required 2-10 treatment courses and the other six 11-19 courses. None of the patients treated by immunotherapy displayed adverse side-effects. Immunotherapy proved to be effective in the treatment of single cutaneous lesions, multiple cutaneous lesions and in cases of mucocutaneous leishmaniasis. In comparison with chemotherapy (Glucantime), immunotherapy is less efficient and more prolonged but can be safely used when antimonials are contra-indicated or are found to be ineffective. Consideration is given to the treatment of victims of ACL living in rural areas remote from a medical centre.
Subject(s)
Immunotherapy, Active , Leishmania/immunology , Leishmaniasis, Cutaneous/therapy , Protozoan Vaccines/therapeutic use , Adolescent , Adult , Aged , Animals , Brazil , Child , Child, Preschool , Female , Humans , Leishmania guyanensis/immunology , Leishmania mexicana/immunology , Leishmaniasis, Cutaneous/drug therapy , Leishmaniasis, Mucocutaneous/drug therapy , Leishmaniasis, Mucocutaneous/therapy , Male , Meglumine/therapeutic use , Meglumine Antimoniate , Middle Aged , Organometallic Compounds/therapeutic useABSTRACT
Previous work in our laboratory, mainly focused the prospects of achieving resistance against Schistosoma mansoni infection with adult worm-derived antigens in the form of a soluble extract (SE). This extract obtained by incubation of living adult schistosomes in saline, contains a large number of distinct molecules and was actually shown to be significantly protective in different outbred animals models such as Swiss mice and rabbits. It thus appeared worthwhile to investigate the potential protective activity of SE in different inbred strains of mice, known to be highly susceptible to the infection. Herein we present data showing that DBA/2 mice, once immunized with SE acquire significant levels of resistance to a S. mansoni cercarial challenge. In addition, preliminary studies on the immune system of immunized animals revealed that, injection of SE caused no general imbalance of B or T cell responses.
Subject(s)
Antigens, Helminth/immunology , Schistosoma mansoni/immunology , Schistosomiasis mansoni/prevention & control , Vaccination , Animals , Antigens, Helminth/isolation & purification , Dermatitis, Contact/immunology , Hemolytic Plaque Technique , Lymphocyte Subsets/immunology , Male , Mice , Mice, Inbred DBA , Schistosomiasis mansoni/immunology , Vaccines/immunologyABSTRACT
Previous studies have shown that both permissive (mouse) and partially permissive (rabbit) hosts develop high levels of resistance against Schistosoma mansoni infection after vaccination with a multiple antigen extract (SE) obtained by incubation of living adult worms in saline, plus bacterial adjuvant. To investigate variables influencing SE-induced protection in murine schistosomiasis, a series of distinct vaccination protocols were performed focussing on the immunization dose, carrier systems, route, site and amplitude of challenge infection, and time between immunization and challenge. In addition, a new approach was adopted to evaluate SE protective activity, by means of population analysis of worm burden frequency distributions in a large scale study of vaccination in outbred Swiss mice. Distinct curves of frequency and a drastic difference in worm burden distribution of frequencies from SE-vaccinated x non-vaccinated mice were found. It was shown that SE could generate 75% mean protection in outbred mice even in the absence of adjuvant. In addition SE immunization was also able to induce full protection against lethal infection. SE-induced protection could be modulated by such parameters as dose of SE immunization/challenge interval, and route of cercariae injection. These data show that SE yields very high protective activity in outbred mice, and may provide a further insight for rational design of a vaccine in experimental schistosomiasis.
Subject(s)
Antigens, Helminth/immunology , Schistosoma mansoni/immunology , Schistosomiasis mansoni/prevention & control , Vaccination , Animals , Dose-Response Relationship, Immunologic , Freund's Adjuvant , Immunization, Secondary , Male , MiceABSTRACT
The Montenegro skin test is widely used as a diagnostic method for American cutaneous leishmaniasis (ACL) but little is known about the histological changes that occur in the skin after administration of the antigen. This report is based on histological studies of biopsied material obtained, from inoculation sites, 48 hours after individuals had been given intradermal injections with a standardized Montenegro antigen. The material examined was obtained from four distinctly different test groups: naturally infected patients with parasitologically proved ACL and with positive Montenegro's reaction; individuals without previous history of ACL and not previously tested with Montenegro antigen; participants in anti-ACL vaccine trials who developed positive reactions to Montenegro antigen after vaccination; other participants in vaccine trials who had negative Montenegro responses after vaccination or had served as controls in the trials. The histological pictures of each group are described and discussed. Histologically, the reactions of vaccinated individuals were indistinguishable from those with naturally acquired infections.
