Leda Quercia Vieira is full Professor at the Department of Biochemistry and Immunology 
Instituto de Ciências Biológicas
Universidade Federal de Minas Gerais
Belo Horizonte, MG, Brazil
She is the President of the Sociedade Brasileira de Bioquímica e Biologia Molecular of Brazil (SBBq) for the period 2020-2022.

Can you introduce yourself and your line of research?


 I graduated in Biology in 1980, and six months later joined the Biochemistry graduate program at Universidade Federal de Minas Gerais (UFMG). I did my MSc trying to understand the reason why infection of germfree mice with Schistosoma mansoni rendered less granuloma and less eggs than when conventional (microbiota bearing) mice were infected by the parasite. We found less proliferation of the cells that form the granuloma, and, since there were less granuloma, we found smaller collagen synthesis in the liver of germfree infected mice. My MSc supervisor advised me to go to Giovanni Gazzinelli´s laboratory, since I was clearly interested in immunology of parasitic diseases. There I studied the reaction of patient´s peripheral blood mononuclear cells to different antigens derived from S. mansoni. I tried to characterize the composition of the S. mansoni cercariae glycocalyx and managed to partially characterize it. I did a post-doc at FioCruz in Belo Horizonte and spent some time at the NIH.

I was hired by UFMG in 1989. At this point, I decided that I had to change parasites if I wanted to remain in the field of parasite immunology, since the cycle of S. mansoni requires the maintenance of the intermediate host, the snail Biomphalaria glabrata, and the definitive host, which fortunately can be mice, but a constant maintenance of the cycle is required, and this was a structure I could not maintain by myself in large scale at UFMG. At this point I was accepted as a post-doc in Phillip Scott´s laboratory, whom I had met at the NIH. I moved then to study host parasite immunology in a different model. Leishmania are parasites very easy to maintain, so I could easily bring the model back to Brazil.

My present line of research is understanding the nuances of host parasite relationship by using different models. We are mainly interested the early inflammatory response caused by different species of Leishmania and the cytokines that are paramount to promote killing of parasites, inflammatory responses and the pattern of response of the host cell, monocytes or macrophages, in different environments (eg. in the absence of interferon-gamma; in the absence of microbiota; when reactive oxygen species are not produced; or when cells do not respond to TNF). We have shown in several models that lesions and parasitism are independent of each other, and their relationship is dependent on the interplay of many factors.


What have been your most important scientific contributions?


I can name three.

- That IL-12 is produced in response to L. major and that it can be used as an adjuvant to induce a Th1 response, which contributes to prevent lesions in mice infected with L. major (Vieira et al., 1994, Immunol. Let. 40:15761; Afonso et al., 1994, Science 263:235).

- That there is a dissociation between the number of parasites in lesions and lesion sizes, and that several factors are responsible for the delicate balance between resistance to parasitism and disease as defined by the size of lesions (Vieira et al., 1996, J. Immunol. 157:827; Oliveira et al., 2012, Clinical & Developmental Immunology 1:12; Carneiro et al., 2015, J. Interf. & Cyt. Res. 35935; Roma et al., 2016, Parasite & Vectors, 9:193; Carneiro et al., 2020 Cell Host & Microbe, 4:1).

- That the indigenous microbiota is essential to determine the outcome of infection with L. major independently of a Th1 response, by modulating macrophage phenotype (Oliveira et al., 2005, Parasitology 131: 477; Lopes et al, submitted).


What have been the main challenges that you have experienced throughout your academic and scientific career and how have you overcome those?


The main challenge I have experienced is lack of funding. Many times, I was not able to overcome it and someone else managed to answer the question I was struggling to answer before me and using more sophisticated tools. When I have overcome it, it was thanks to brilliant students, creativity, and luck.

What are the major challenges faced by female scientists at your Institution?


My generation was the first that started doing research in my Institution in significant numbers and professionally. Before us, a few strong and courageous women managed to perform well, but a lot of criticism of their attitude (being too aggressive, etc.) was witnessed by me. The other challenge is to convince oneself that one is not inferior because men are more assertive. It took me and my generation a long time to realize that we were just as good, just reacted differently to challenges, and that did not mean that we were not overcoming obstacles as well as men, but in a different way. Although I have not had children, I am sure that this is also a big challenge for women, even younger ones.

The Covid 19 pandemic has shown that a segment of the population does not believe in scientific evidence. In your opinion why is there this discredit of science? How to change this perception?


  1. Magic solutions, like those provided by faith, prayer, belief in the supernatural, are more soothing than believing that a disease can or cannot be overcome by hard work and hard-to-take measures such as isolation.

  2. Lack of education. People do not receive a real Science education. They take Science classes just like Literature classes. The scientific method should be taught by showing students how to do Science and how to torture a hypothesis until it survives all your trials to disprove it.

  3. Most people suffer from functional illiteracy.

  4. I think, specifically in the case of Covid-19, that the internet is also responsible for the population not to believe in scientific evidence. For a few years now, since so many social media are available, anyone can give their opinion about anything and be heard. Well, not everyone knows what they are talking about, from trivia to Science.


Logo of the Laboratory of Gnotobiology and Immunology headed by Professor Vieira.