In the early 1960s the discovery that neonatally thymectomized mice have impaired immune responses [1, 2] heralded a scientific revolution in immunology. A few years later, in 1966, immunology was further startled by the observation that, in mice, neonatal thymectomy causes lymphocyte depletion in specific areas of the secondary lymphoid organs. Such areas were called “thymus‐dependent areas” by the first persons to describe them, Delphine Parrott and Maria de Sousa [3, 4]. These two scientists working at the Imperial Cancer Research Fund, Mill Hill, London, further concluded that “the thymus produces cells which directly contribute to the migratory or circulatory lymphocyte population but that there also exists another source of supply for the plasma cells series. These two systems may function synergistically (…)” [3]. The T and B cell zones had arrived.

Maria de Sousa (M.D. Lisbon 1963, Ph.D. Glasgow, 1971), co‐author of this ground‐breaking observation passed away on April 14^th, 2020 victim of the SARS‐CoV‐2 pandemic.

In 1971, Maria working at the Department of Immunology, Western Infirmary, Glasgow, showed in an elegant study that after intravenous injection, mouse thymus and marrow cells, display different migratory patterns and homed into the previously described T and B areas, respectively [5]. She concluded that those cell populations have the ability to distinguish different environments and then home specifically to them, and christened this phenomenon “ecotaxis” [5]. In 1971 this idea was both visionary and conceptually brilliant, and is still very striking nowadays, when mentions of cellular niches (e.g. the hematopoietic stem cell niche, the plasma cell niche, etc.) are so common. This is a clear example of Maria's original and forward thinking, and reminds us how creativity in science opens new perspectives and avenues of research. It is a fundamental paper that those who discuss cellular niches and micro‐environments should still praise and cite.

We write this brief note of tribute, because we were Maria's first Ph.D. students between 1973–1977, first in Glasgow and then in New York. It was a period of much work, countless discussions, lots of fun and we are thankful for all of it. Our careers diverged afterwards, but we stayed in permanent contact and kept a deep friendship across the years, in Paris, Porto and Lisbon.

In 1984, Maria decided to return to Portugal where she assumed the position of Professor of Immunology at the Medical School of the Instituto Abel Salazar, in Porto. She established a research program on hemochromatosis, a disease with particularly high incidence in the North of Portugal, and studied the possible role of iron in the immune system. She continued to contribute significantly to scientific knowledge, describing, for example, alterations of iron homeostasis in β2‐microglobulin mice [6], a finding supported when a novel MHC class‐I like gene (HFE) was shown to control iron metabolism [7].

She was elected president of the Portuguese Society for Immunology (1982‐1988) and General Secretary of the European Federation of Immunological Societies from 1986–1992.

After moving back to Portugal in the 1980s, Maria had a substantial impact on Science Policy in the country. Firstly, early after her return she was invited by the late Jose Mariano Gago (1948‐2015), then President of the National Research Council, to head the science committee for biomedical research. She introduced, external peer review of projects and institutions, a practice that, unfortunately, is not yet fully implemented in all Portuguese universities.

Secondly, for the first time in a Portuguese University, a Professor undertook to establish a doctoral program. Being persistent, persuasive, and socially smart she managed to create an Immunology MSc. Program (1984), which later, in 1996, developed into the GABBA Ph.D. program (https://gabba.up.pt/), covering all fields of biology and biomedical research at the University of Porto. This program was unique in providing all students with four‐year Ph.D. scholarships and giving them the freedom to choose the subject, supervisor and laboratory to perform their thesis, either in Portugal or abroad.

These measures transformed science in Portugal, and were responsible for the emergence of a new generation of Portuguese scientists, including immunologists, some of which have become top ranked in the world.

We collaborated in the GABBA program from 1986 to 2014 and witnessed Maria's enthusiasm and devotion. She always kept close contact with all students, whatever their area of research, discussed their projects and their work, and provided guidance, encouragement, help and support. Moreover, she extended her interest and generous advice to any other research biologists that would seek for her assistance. She also took a decisive role in the perception of science in Portugal.

In addition to her passion for science Maria had many other interests. She was fond of art, in particular music (she was a piano player herself) and literature. She often participated in cultural events and was also an excellent poet. Her last poem (“Love letter in a viral pandemic”) was dedicated to all GABBA students. A touching farewell [8].

Maria was respected and much loved by many. She will be greatly missed.

Rest in peace Maria. Don't worry; your hopes and vision are still alive!

在1960年代初期，新生儿经胸腺切除的小鼠的免疫反应受损[ 1、2 ]的发现预示着免疫学的科学革命。几年后，即1966年，免疫学又因观察到小鼠胸腺切除导致次级淋巴器官特定区域的淋巴细胞耗竭而更加震惊。最早描述这些区域的人称为Delphine Parrott和Maria de Sousa [ 3，4 ]。伦敦米尔山帝国癌症研究基金会的这两位科学家进一步得出结论，“胸腺产生的细胞直接有助于迁移或循环淋巴细胞的繁殖，但浆细胞系列也有另一种供应来源。这两个系统可以协同工作（…）” [ 3 ]。T细胞区和B细胞区已经到达。

玛丽亚·德·索萨（Maria de Sousa）（1963年，里斯本，博士学位，格拉斯哥，1971年）的这项突破性观察的合著者于2020年4月14^日去世，成为SARS-CoV-2大流行的受害者。

1971年，玛丽亚（Maria）在格拉斯哥西部医务所免疫学部门工作，在一项优雅的研究中表明，静脉注射后，小鼠胸腺和骨髓细胞显示出不同的迁徙方式，并分别进入了先前描述的T和B区[ 5 ]。她得出的结论是，这些细胞群能够区分不同的环境，然后专门适应它们，并称这种现象为“ ecotaxis” [ 5]。在1971年，这个想法既富于远见，又在概念上非常出色，并且在当今，当提到细胞壁ni（例如造血干细胞壁iche，浆细胞壁iche等）时，这种想法仍然非常引人注目。这是玛丽亚原始和前瞻性思维的明确例子，并提醒我们科学创造力如何为研究开辟新的视角和途径。这是一份基本论文，那些讨论细胞生态位和微环境的人仍应赞扬和引用。

我们写此简短的致敬笔记，因为我们是Maria的第一位博士学位。1973年至1977年之间的学生，首先在格拉斯哥，然后在纽约。那段时期的工作很多，讨论不计其数，很有趣，我们对此表示感谢。此后，我们的职业有所不同，但多年来，我们在巴黎，波尔图和里斯本一直保持着长期联系并保持着深厚的友谊。

1984年，玛丽亚（Maria）决定返回葡萄牙，在波尔图的阿贝尔·萨拉扎（Abel Salazar）医学院担任免疫学教授。她建立了一项关于血色素沉着病的研究计划，该病在葡萄牙北部的发病率特别高，并且研究了铁在免疫系统中的可能作用。她继续为科学知识做出重要贡献，例如描述了β2-微球蛋白小鼠中铁稳态的改变[ 6 ]，这一发现在新型MHC I类基因（HFE）被证明可以控制铁代谢时得到了支持[ 7]。 ]。

她当选为葡萄牙学会免疫学（1982- 1988年）和秘书长欧洲联邦免疫学会的会长，从1986-1992。

在1980年代回到葡萄牙后，玛丽亚对该国的科学政策产生了重大影响。首先，回国后不久，她受已故的国家研究委员会主席何塞·马里亚诺·加戈（Jose Mariano Gago）（1948-2015）邀请担任生物医学研究科学委员会的负责人。她介绍了对项目和机构的外部同行评审，很遗憾，这种做法尚未在所有葡萄牙大学中得到充分实施。

其次，一位教授首次在葡萄牙大学里建立了博士学位课程。她坚持不懈，具有说服力并且在社交上很聪明，因此设法创建了免疫学理学硕士。计划（1984），后来在1996年发展为GABBA博士学位。计划（https://gabba.up.pt/），涵盖波尔图大学的生物学和生物医学研究的所有领域。该计划的独特之处在于为所有学生提供了四年制博士学位。奖学金，并赋予他们在葡萄牙或国外自由选择主题，指导者和实验室以执行其论文的自由。

这些措施改变了葡萄牙的科学，并导致了包括免疫学家在内的新一代葡萄牙科学家的出现，其中一些已成为世界排名最高的科学家。

从1986年到2014年，我们参与了GABBA计划，并见证了Maria的热情和奉献精神。她始终与所有学生保持密切联系，无论他们研究哪个领域，都讨论了他们的项目和工作，并提供了指导，鼓励，帮助和支持。此外，她向其他寻求其帮助的研究生物学家表示了兴趣并提供了慷慨的建议。她在葡萄牙对科学的认识中也起着决定性的作用。

除了对科学的热情外，玛丽亚还有许多其他兴趣。她喜欢艺术，特别是音乐（她自己是钢琴演奏者）和文学。她经常参加文化活动，也是一位出色的诗人。她的最后一首诗（“病毒性大流行中的情书”）献给了所有GABBA学生。感人的告别[ 8 ]。

玛丽亚受到许多人的尊重和深爱。人们会深切的怀念她的。

安息吧玛丽亚。不用担心 您的希望和远见依然存在！