Kevin R. Macaluso, PhD
Dr. Kevin R. Macaluso, Chair of the Department of Microbiology and Immunology, received his Baccalaureate Degree from Colorado State University, his Master's Degree from Sul Ross State University, and his Ph.D. from Oklahoma State University.
Before becoming Locke Distinguished Chair in the Department of Microbiology and Immunology, Dr. Macaluso was the Mary Louise Martin Professor in the Department of Pathobiological Sciences at Louisiana State University (LSU) in Baton Rouge, Louisiana.
Vector-borne Disease and Rickettsiology
Vector-borne diseases are major causes of death and illness worldwide and a large and growing public health problem in the United States. The Macaluso lab employs biologically relevant host/vector/pathogen systems to investigate the determinants of pathogen transmission and subsequent disease.
Rickettsial Transmission via Blood-Feeding Arthropods
The research of the Macaluso lab group encompasses the molecular and biological mechanisms central to rickettsial transmission by blood-feeding arthropods. In the laboratory, they have established two unique systems consisting of slow- and fast-feeding vectors with which to study rickettsial transmission. The first line of research is directed at deciphering the molecular mechanisms associated with Rickettsia infection of ticks and how both tick- and bacterial-derived factors mediate infection.
Ongoing research activities in this area are supported by the NIH/NIAID and emphasize the roles of microbial determinants in successful vector infection. Specifically, Dr. Macaluso and his team are working to define the contribution of conserved surface cell antigens (Sca) to SFG Rickettsia infection of the tick vector. Sca proteins are essential to rickettsial infection and dissemination in vertebrate cells. They hypothesize that there will be a distinct profile of rickettsial proteins necessary for infection in the arthropod vector. The objective of their studies is to define the role for rickettsial proteins during the infection process in the tick host through targeted mutagenesis in rickettsial species and analysis of isogenic rickettsial mutants in tick cell interactions in vitro and in vivo.
Additionally, they are investigating how the tick immune response to SFG Rickettsia correlates to vector competence. A differential tick response to individual species of SFG Rickettsia supports a species-specific host response to rickettsial infection. Therefore, they hypothesize that a central molecule, Relish, is responsible for the balance between successful rickettsial colonization and clearance from the arthropod host. Current experiments aim to delineate the IMD immune signaling system focusing on the production of active Relish in the tick host. They are also working to determine if differential responses and downstream effectors play a role in successful rickettsial colonization of the tick host.
A major goal of Dr. Macaluso’s research is to provide a better understanding of the constituents of rickettsial transmission and maintenance in arthropod vectors. Ultimately, appreciation of the biology of transmission will lead to the identification of novel points of intervention.See More
Flea-borne Rickettsioses--Rickettsia felis
Another currently NIH/NIAID supported project in the Macaluso laboratory focuses on an emerging flea-borne rickettsioses, caused by Rickettsia felis. Originally identified in the United States as a human pathogen in 1991, it is now recognized that human infections caused by R. felis account for up to 15% of the cases of fever among non-malarial conditions in sub-Saharan Africa. Specifically, they are delineating the mechanisms by which Rickettsia felis is acquired and transmitted by arthropods. They are testing the hypothesis that transmission of R. felis occurs between fleas, and that newly infected fleas can perpetuate the infection within a flea population. The objective of this research is to identify novel routes of R. felis acquisition by fleas and assess the intra- (cat flea, Ctenocephalides felis) and inter- (Oriental rat flea, Xenopsylla cheopis) specific transmission of R. felis.
Ongoing studies are investigating novel routes of vertebrate infection and the host immune response during exposure and infection. At the same time, they are defining the R. felis-derived molecular constituents of transmission by flea vectors. They’ll test the hypothesis that the expression of distinct rickettsial protein profiles orchestrate R. felis infection of arthropods and is actively involved in effective transmission. Dr. Macaluso and the researchers in his lab are focusing on targeted mutagenesis in R. felis and analysis of isogenic R. felis mutants and natural field-derived variants in flea-infection and transmission. The unique vector attributes, combined with a relatively understudied rickettsial biology, provide a rich area of research.
Bacteria and Arthropod Transmission and Infection
In addition to the primary research activities outlined above, they have several collaborative projects in various stages of development, including the recently funded exploratory grant on potential transmission of Mycobacterium leprae by hematophagous arthropods and two projects examining bacterial (Bartonella and Rickettsia) regulatory responses during arthropod infection and transmission.