Nova abordagem tem como alvo o norovírus, principal causa mundial de infecção alimentar
Todos os anos, o norovírus causa centenas de milhões de casos de intoxicação alimentar – e a morte de pelo menos 50.000 crianças – mas não existe uma maneira real de controlá-lo. O vírus provou ser excepcionalmente difícil de estudar em laboratório..
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)
Células intestinais (núcleos mostrados em azul) são infectadas com uma cepa de rotavírus geneticamente modificada para carregar um gene do norovírus (verde). Pesquisadores da Escola de Medicina da Universidade de Washington em St. Louis descobriram uma maneira criativa de fazer uma vacina para o norovírus, a principal causa de infecções transmitidas por alimentos, pegando carona no rotavírus, um vírus não relacionado para o qual já existem várias vacinas altamente eficazes. Crédito: Takahiro Kawagishi/Washington University
Todos os anos, o norovírus causa centenas de milhões de casos de intoxicação alimentar – e a morte de pelo menos 50.000 crianças – mas não existe uma maneira real de controlá-lo. O vírus provou ser excepcionalmente difícil de estudar em laboratório, e os cientistas lutaram para desenvolver vacinas e medicamentos eficazes.
Um novo estudo da Escola de Medicina da Universidade de Washington, em St. Louis, descreve uma maneira criativa de fazer uma vacina contra o norovírus pegando carona nas vacinas altamente eficazes contra o rotavírus, um vírus não relacionado que também causa diarreia.
Os pesquisadores criaram uma vacina experimental combinada rotavírus-norovírus, adicionando uma proteína-chave do norovírus a uma cepa inofensiva de rotavírus. Camundongos que receberam a vacina experimental produziram anticorpos neutralizantes contra rotavírus e norovírus. O estudo, disponível online em Proceedings of the National Academy of Sciences , descreve uma abordagem inovadora para prevenir uma das infecções virais mais comuns e intratáveis.
"Praticamente todo mundo já teve norovírus em algum momento", disse o autor sênior Siyuan Ding, Ph.D., professor assistente de microbiologia molecular. "Você sai para comer, e a próxima coisa que você sabe é que está vomitando e tendo diarréia. Você vai se recuperar, mas vai ser uns três dias difíceis. Para crianças no mundo em desenvolvimento que não têm acesso a água limpa, no entanto, pode ser mortal. As vacinas contra o rotavírus funcionam muito bem e já existem sistemas de distribuição global configurados para elas, então, com base nisso, vimos uma oportunidade de finalmente fazer algum progresso contra o norovírus."
Antes das primeiras vacinas contra o rotavírus serem lançadas em 2006, meio milhão de crianças em todo o mundo morriam todos os anos de diarreia causada pela infecção por rotavírus. Agora, o número é estimado em cerca de 200.000 - ainda alto, mas uma grande melhoria. Quatro vacinas contra o rotavírus estão em uso em todo o mundo. Todas são vacinas de vírus vivos, o que significa que são baseadas em formas enfraquecidas de rotavírus capazes de desencadear uma resposta imune , mas não de deixar as pessoas doentes.
O norovírus humano, por outro lado, bloqueou a investigação científica por décadas. Ele não infecta camundongos ou ratos ou qualquer outro animal de laboratório comum, portanto, os tipos de experimentos que levaram ao desenvolvimento de vacinas contra o rotavírus têm sido impossíveis de replicar com o norovírus.
Ding e seus colegas - incluindo o primeiro autor Takahiro Kawagishi, Ph.D., um cientista da equipe do laboratório de Ding, e o autor correspondente Harry B. Greenberg, MD, professor emérito de medicina na Universidade de Stanford - tiveram a ideia de usar rotavírus para contornar as dificuldades técnicas de trabalhar com norovírus. Eles trabalharam com uma cepa de rotavírus de laboratório como um substituto para uma das vacinas contra rotavírus aprovadas, que são proprietárias.
Os pesquisadores inseriram o gene da proteína que forma a superfície externa do norovírus humano no genoma da cepa de laboratório do rotavírus. Em seguida, eles administraram o rotavírus modificado a camundongos infantis imunocomprometidos por via oral, da mesma forma que as vacinas contra o rotavírus são dadas às crianças. Eles coletaram amostras de sangue e fezes quatro, seis e oito semanas depois. Nove semanas após a imunização inicial, os pesquisadores deram aos camundongos um reforço por injeção e coletaram amostras novamente uma semana depois.
Uma forte resposta de anticorpos foi evidente no sangue de nove dos 11 camundongos testados e nos intestinos de todos os 11 camundongos. Melhor ainda, alguns dos anticorpos do sangue e dos intestinos foram capazes de neutralizar ambos os vírus em culturas de "mini-intestino" humano em um prato. Essas culturas, também conhecidas como organóides, são cultivadas a partir de células-tronco humanas e replicam a superfície do intestino humano.
"Tradicionalmente, os estudos de vacinas se concentram na resposta de anticorpos no sangue, porque entendemos melhor essa parte da resposta imune", disse Ding. "Mas o norovírus e o rotavírus são vírus intestinais, então os anticorpos no sangue são menos importantes do que os do intestino em termos de combate a esses vírus. O fato de termos visto uma forte resposta de anticorpos no intestino é um bom sinal."
O próximo passo é mostrar que os animais imunizados com a vacina experimental têm menos probabilidade de adoecer ou morrer de norovírus . Ding tem tais experimentos em andamento.
O poder deste estudo é que ele descreve uma nova abordagem que pode acelerar o desenvolvimento de vacinas para uma variedade de organismos problemáticos que causam diarreia, especialmente em países com recursos limitados, onde ocorrem muitas dessas infecções.
“Existem muitos patógenos intestinais para os quais não temos bons tratamentos ou vacinas”, disse Ding. "Em princípio, poderíamos colocar um gene de qualquer organismo que infectasse o trato intestinal na vacina contra o rotavírus para criar uma vacina bivalente. Teríamos que encontrar os alvos certos para produzir uma boa resposta imune, é claro, mas o princípio é simples.
"Como cientistas básicos, raramente temos a chance de realmente levar algo adiante na clínica", continuou Ding. "Nós estudamos o que o vírus faz e como o hospedeiro responde em um nível básico. Esta é uma rara oportunidade para nosso trabalho afetar diretamente a saúde humana e tornar a vida das pessoas melhor."
Mais informações: Takahiro Kawagishi et al, Anticorpos neutralizantes mucosos e sistêmicos para norovírus induzidos em camundongos infantis oralmente inoculados com rotavírus recombinantes, Proceedings of the National Academy of Sciences (2023). DOI: 10.1073/pnas.2214421120
Informações do periódico: Proceedings of the National Academy of Sciences