Data/hora: 03/06/2024 05:23:32

Provedor de dados: | Brazilian Journal of Medical and Biological Research
País: | Brazil
Título: | Interferon gamma is a key cytokine in lung phase immunity to schistosomes but what is its precise role?
Autores: | Wilson,R.A.
Data: | 1998-01-01
Ano: | 1998
Palavras-chave: | Interferon gamma; Schistosoma mansoni; Lung phase immunity; Nitric oxide; Adhesion molecule.
Resumo: | Vaccination of mice with radiation-attenuated cercariae of Schistosoma mansoni induces a high level of protection against challenge with normal larvae. The immune effector mechanism, which operates in the lungs, is a cell-mediated delayed-type hypersensitivity response and involves the formation of a tight focus of mononuclear cells around embolised larvae. CD4+ T cells with Th1 characteristics are a major component of the infiltrate. They secrete abundant interferon gamma (IFN&lt;FONT FACE="Symbol"&gt;g&lt;/font&gt;) upon antigen stimulation in vitro, whilst in vivo neutralisation of the cytokine results in 90% abrogation of immunity. IFN&lt;FONT FACE="Symbol"&gt;g&lt;/font&gt; can induce a large number of genes and an attempt has been made to identify the ones which are essential components of the effector mechanism. Inducible nitric oxide synthase (iNOS) is such a candidate and nitric oxide (NO) is produced by cultures of airway leucocytes from the lungs of vaccinated mice post-challenge. However, the continued resistance of mice with a disrupted iNOS gene indicates that NO has only a minor role in the protective response. Mice with a disrupted IFN&lt;FONT FACE="Symbol"&gt;g&lt;/font&gt; receptor gene have been used to dissect the role of the cytokine. After vaccination and challenge, CD4+ T cells from the pulmonary interstitium have reduced levels of ICAM-1 and LFA-1 expression, compared to wild-type animals, which coincides with a reduced cohesiveness of foci. However, immunity is not significantly impaired in mice with a disrupted ICAM-1 gene, and focus formation is normal. Similarly, a role has not been found for CD2/CD48 interactions in cell aggregation. Possible IFN&lt;FONT FACE="Symbol"&gt;g&lt;/font&gt;-inducible molecules yet to be fully investigated include other ligand-receptor pairs, chemokines, and tumour necrosis factor &lt;FONT FACE="Symbol"&gt;a&lt;/font&gt;.
Tipo: | Info:eu-repo/semantics/article
Idioma: | Inglês
Identificador: | http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X1998000100022
Editor: | Associação Brasileira de Divulgação Científica
Relação: | 10.1590/S0100-879X1998000100022
Formato: | text/html
Fonte: | Brazilian Journal of Medical and Biological Research  v.31 n.1 1998
Fonte: | info:eu-repo/semantics/openAccess