Impact of malnutrition on immunity and infection

Malnutrition may be a consequence of energy deficit or micronutrient deficiency. It is considered the most relevant risk factor for illness and death, particularly in developing countries. In this review we described the magnitude of this problem, as well as its direct effect on the immune system and how it results in higher susceptibility to infections. A special emphasis was given to experimental models used to investigate the relationship between undernutrition and immunity. Malnutrition is obviously a challenge that must be addressed to health authorities and the scientific community

THE RELEVANCE OF NUTRITIONAL STATUS AND HISTOPATHOLOGICAL FINDINGS ON THE INFECTIOUS PROCESS OF BALB/C MICE INOCULATED WITH Lacazia loboi

SUMMARY The aim of this study was to evaluate the effects of the protein-calorie malnutrition in BALB/c isogenic mice infected with Lacazia loboi, employing nutritional and histopathological parameters. Four groups were composed: G1: inoculated with restricted diet, G2: not inoculated with restricted diet, G3: inoculated with regular diet, G4: not inoculated with regular diet. Once malnutrition had been imposed, the animals were inoculated intradermally in the footpad and after four months, were sacrificed for the excision of the footpad, liver and spleen. The infection did not exert great influence on the body weight of the mice. The weight of the liver and spleen showed reduction in the undernourished groups when compared to the nourished groups. The macroscopic lesions, viability index and total number of fungi found in the footpads of the infected mice were increased in G3 when compared to G1. Regarding the histopathological analysis of the footpad, a global cellularity increase in the composition of the granuloma was observed in G3 when compared to G1, with large numbers of macrophages and multinucleated giant cells, discrete numbers of lymphocytes were present in G3 and an increase was observed in G1. The results suggest that there is considerable interaction between Jorge Lobo's disease and nutrition

Acute Strongyloides venezuelensis infection did not prevent EAE development: implications for hygiene hypothesis

Prevalence of allergic and autoimmune pathologies is clearly increasing in developed countries. This has been attributed to a decreased exposure to certain microorganisms and been referred as hygiene hypothesis. In this study we evaluated if a previous infection with Strongyloides venezuelensis would alter the progression of experimental autoimmune encephalomyelitis (EAE) in Lewis rats. Animals were initially infected with 4000 L3 infective larvae of S. venezuelensis by subcutaneous route. Encephalomyelitis was then induced during the acute phase of the infection by immunization with myelin basic protein emulsified with Complete Freund's Adjuvant plus Mycobacterium butyricum. Previous infection downmodulated cytokine production but did not change clinical and histopathological EAE manifestations. Cytometric analysis with antibodies specific for CD4+CD25+Foxp3+ regulatory T cells indicated that infection also did not alter the frequency of these cells in spleen and regional lymph nodes. This finding could partly explain the failure of this worm to avoid EAE progression. Altogether these results demonstrated that infection with S. venezuelensis was not able to modify EAE progression in Lewis rats. In the context of the hygiene hypothesis, these results reinforce the necessity of a comparative study among different helminth species to identify the ones with immunoregulatory competence

Acute Strongyloides venezuelensis infection did not prevent EAE development: implications for hygiene hypothesis

Prevalence of allergic and autoimmune pathologies is clearly increasing in developed countries. This has been attributed to a decreased exposure to certain microorganisms and been referred as hygiene hypothesis. In this study we evaluated if a previous infection with Strongyloides venezuelensis would alter the progression of experimental autoimmune encephalomyelitis (EAE) in Lewis rats. Animals were initially infected with 4000 L3 infective larvae of S. venezuelensis by subcutaneous route. Encephalomyelitis was then induced during the acute phase of the infection by immunization with myelin basic protein emulsified with Complete Freund's Adjuvant plus Mycobacterium butyricum. Previous infection downmodulated cytokine production but did not change clinical and histopathological EAE manifestations. Cytometric analysis with antibodies specific for CD4+CD25+Foxp3+ regulatory T cells indicated that infection also did not alter the frequency of these cells in spleen and regional lymph nodes. This finding could partly explain the failure of this worm to avoid EAE progression. Altogether these results demonstrated that infection with S. venezuelensis was not able to modify EAE progression in Lewis rats. In the context of the hygiene hypothesis, these results reinforce the necessity of a comparative study among different helminth species to identify the ones with immunoregulatory competence