CV Science

Maha Zohra Ladjemi PhD in immunology and respiratory research

Course and current status

After an engineer diploma in Biotechnology completed in 2004 in Tunisia, I graduated a master degree in health biology in 2005 in Montpellier. Thereafter, I conducted my PhD work in the field of tumor immunology in the group of Dr. André Pèlegrin (Institute in Cancer Research of Montpellier, Immunotargeting and Radiobiology in Oncology team Inserm U1194). I completed my thesis in 2008 with the highest degree (Suma Cum Laude with the congratulations of jury members) and continued to work in my lab until the end of 2009 to finalize the experiments of the end of my PhD. To acquire further qualifications and expertise, I fulfilled two university degrees (DU in Clinical research at the University of Medicine of Montpellier in 2010 and a Master of management in 2018 at the Brussels Management school ICHEC). I have joined the group of Pr. Charles Pilette (Université Catholique de Louvain, Institute of Experimental and Clinical Research, Pneumology research pole in Belgium) and worked in the field of respiratory research from October 2010 to February 2016 as a post-doctoral researcher. I then joined the group of Dr. Marina Pretolani in Paris (Inserm UMR1152) from March 2016 to July 2018 where I continued to work on the field of the pathophysiology of respiratory diseases. Now, I am working at the Institut Cochin in Paris (Inserm U1016, CNRS UMR8104, Université de Paris – Team Pulmonary and systemic immune responses during bacterial infections) since December 2018 in the group of Prs Jean-Daniel Chiche and Pierre-Régis Burgel where I have in charge an ANR funded project (co-PIs Prs. Frédéric Pène Hôpital et Institut Cochin and Vassili Soumelis Hôpital Saint-Louis). My current work is focusing on the field of nosocomial infections (among them the ones from pulmonary origin) acquired in Intensive Care Unit.

Scientific summary

My current and past research has focused on immunotherapy in oncology and in mucosal immunology and physiopathology of respiratory diseases.

My thesis project in Montpellier (Institut de Recherche en Cancérologie de Montpellier U 1194) focused on anti-HER2 vaccination in breast cancer with the hypothesis that the use of anti-idiotypic antibodies capable of mimicking the tumor antigen HER2 could break the immune tolerance against this self antigen. Using cancer cell lines, two mouse models and the bioluminescence tool we confirmed the concept of antigenic mimicry as a means for breaking immune tolerance against self antigens. Thus, we have demonstrated the efficacy of a human antibody vaccine candidate in breaking immunological tolerance to the HER2 tumor antigen, in protecting mice against the development of HER2 + breast tumors and we have identified the associated immunological response.

I then concentrated my research during my first post-doc in Brussels (Université Catholique de Louvain) on B lymphocyte responses with a main focus on IgA production as a first line defense at mucosal sites. Chronic airway diseases such as chronic obstructive pulmonary diseases (COPD) and asthma maybe initiallythe result of adysfunctionof the bronchial epithelium. I have explored key mechanisms and consequences of such epithelial dysfunction especially for IgA production (by B lymphocytes) and transport (by the bronchial epithelium) in COPD and asthma using lung sections and an ex vivo relevant model of air-liquid interface epithelial differentiation from surgical specimens or biopsies. Overall, my work led to different key observations on lung host defence in chronic airway diseases. More specifically in COPD, evidence of local IgA up-regulation within lung lymphoid follicles and the link with chronic infection provided by our study is of great importance. Moreover, because lung lymphoid follicles are not restricted to COPD, our study has wider significance.  Besides, we also demonstrated an alteration of the trans-epithelial transport of IgA in asthma mediated by Th2 immune activation which probably affects the first line defense mediated by the secretory IgA system.

Thereafter, I studied during my second post-doc in Paris (Inserm UMR1152), the effect of bronchial thermoplasty a newly developed therapy for severe asthmatic patients, targeting smooth muscle. We hypothesized that the clinical benefit observed with this therapy could also imply, besides smooth muscle size reduction, a direct effect on bronchial epithelium. Using biopsies sections and the ex vivomodel of bronchial epithelial differentiation previously established during my first post-doc, we better characterized some of the mechanisms linked to the clinical benefit of bronchial thermoplasty and identified aspects of epithelial responses related to inflammation of the bronchial mucosa.

Now, my current research at the Institut Cochin in Paris (Inserm U1016, CNRS UMR8104, Université de Paris)is focusing on the immune mechanisms underlying the susceptibility to nosocomial infections (the most frequent and severe being pneumonia) acquired in intensive care unit in septic patients.