Coxiella burnetii is a Gram-negative bacterium and causative agent of Q fever in humans. The bacterium is highly adapted to infect alveolar macrophages and subvert their functions, including the avoidance of TLR recognition, the inhibition of apoptosis and the modulation of diverse vesicle traffic pathways. Its virulence is dependent on the translocation of bacterial proteins (called effectors) into the host cytoplasm through the Dot/Icm T4BSS, creating a spacious intracellular vacuole that supports bacterial replication. Similar to Coxiella, Legionella pneumophila virulence depends on its T4BSS, however, Legionella is more suitable for genetic manipulation, a feature that supports the use of Legionella as surrogate host to express Coxiella effectors. We generated a library of 66 L. pneumophilla flaA mutants expressing Coxiella effectors. We screened this library and identified 3 Coxiella effectors that may be involved in the manipulation of macrophage functions. Expression of these 3 effectors by L. pneumophila led to decreased pyroptosis (measured by LDH release and pore formation assays) and increased cytokine production (IL-1β and IL-6). Thus, we aim to further study these effectors expressing them in eukaryotic cells, identify the possible eukaryotic partner and obtain Coxiella mutants for each effector. This study may help to elucidate the function of these effectors, providing information for our understanding of the evasive mechanisms used by intracellular pathogens to subvert the host cell mechanisms. In addition, this study will lead to the identification of target molecules and pathways to the development of immunological therapies.