Research - Institute of Genetics - Immunology Unit - Laboratory of Immunology

István ANDÓ
scientific adviser

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Éva KURUCZ senior research associate
Viktor HONTI research associate
Róbert MÁRKUS research associate
Gyöngyi CINEGE research associate
János ZSÁMBOKI research associate
Gábor CSORDÁS junior research associate
Beáta KARI Ph.D. student
Zita LERNER Ph.D. student
Gergely VARGA Ph.D. student
Erika GÁBOR Ph.D. student
Anita BALÁZS laboratory assistant
Olga KOVALCSIK laboratory assistant
Anikó KÉPÍRÓ laboratory assistant

LABORATORY OF IMMUNOLOGY

Innate immunity

Immunity is the first line of defense against microbes and other invaders. The microbial and parasitic attacks and tumors in the animal kingdom are controlled by the innate immunity: production of antimicrobial peptides, phagocytosis and the encapsulation reaction. The fruit fly, Drosophila melanogaster, possesses an effective immune system, the prototype of the innate immunity of vertebrates. Our studies are carried out with the hope of revealing and understanding the immune mechanisms conserved throughout evolution.

Projects

Our group focuses on:
1) Drosophila cell-mediated immunity 2) Functional analysis of an evolutionarily conserved chromosomal region, the nim- region, and the Nimrod receptor family in Drosophila 3) Cell-mediated immunity of the honey bee, Apis mellifera


1) Cell-mediated immunity of Drosophila

We study the immune system of Drosophila melanogaster and other Drosophila species in the hope of exploring the basic mechanisms of blood cell development and cellular immunity to understand different defense strategies utilized to eliminate invaders. So far, we have developed tools for in vitro and in vivo studies in the form of antibodies and fluorescent genetic markers to study Drosophila blood cells. We used them to define major classes and lineages of hemocytes, identified a major source of immune-responsive blood cells in the larva, and showed the plasticity of the phagocytic cell population in the cell-mediated immune responses.

We further define immunological markers for functionally and developmentally distinct hemocyte subsets in Drosophila and develop in vivo genetic markers to trace hemocyte lineages.



Figure 1: Hemocyte types in Drosophila melanogaster



We analyze the compartmentalization of hematopoietic tissues and hemocytes and study the communication between the blood cell compartments, e.g., the sessile hematopoietic tissue with the circulating blood cells as well as with other tissues in the course of the development and the activation of Drosophila blood cells.



Figure 2: Hematopoietic compartments of Drosophila melanogaster. >The lymph gland (LG) the sessile hematopoietic tissue (ST) the posterior hematopoietic tissue (PHT) and the circulating blood cells (C).


We apply a restricted genetic screen to identify key genes involved in activating cellular immunity and to study the role of some of the genes found in cellular immunity and blood cell tumors. We also study the plasticity of hemocyte subsets during the immune response, and we aim to identify mechanisms that transcriptionally or epigenetically define transitions from one cell type (e.g. phagocytic) to another (e.g. encapsulating).



Figure 3: Plasticity of hemocyte lineages and blood cell compartments of Drosophila melanogaster


2) Functional analysis of an evolutionarily conserved chromosomal region, the nim-region, and the Nimrod receptor family in Drosophila

We found members of multiple gene families in each other's direct genomic vicinity on the second chromosome of Drosophila melanogaster - the Nimrod gene superfamily. The analysis of the complete genomes of twelve Drosophila species shows that this gene cluster is one of the largest synthenic regions; the majority of these genes can be found in clusters in all these genomes, and the order of the genes is the same. The majority of these genes show a similar expression profile in different conditions suggesting that they are co-regulated. The cluster is conserved throughout a broad evolutionary timescale. The importance of the Nimrod gene superfamily is further highlighted as the overall composition (presence and order of the genes) seems to be well conserved, but the actual number and orientation of genes in individual gene families vary widely. Since we suspect that the phylogenetic conservation of this region is the result of evolutionary pressure, we undertake studies to explain how the genes of this chromosomal region may act as a functional unit, thereby providing an attracting object for further studies of innate immunity in insects.

The Nimrod proteins of D. melanogaster (e.g. NimC1, NimA, NimB1, NimC4 and Eater) bind bacteria or are involved in the phagocytosis of bacteria and the clearance of apoptotic cells. Other genes of the Nimrod region, such as the Ance genes, may encode for proteases with broad substrate specificity which participate in the immune defense of the insects while the protein encoded by the CenG gene is expressed in the phagosomes of the fruit fly suggesting that it may be involved in phagocytosis. The expression of the Vajk genes increases in response to bacterial infection. These data suggest that the Nimrod gene superfamily plays a role in the immune response.

We have built and are testing a model which could explain why the genes of the Nimrod chromosomal region may act as a functional unit and why the co-evolution of the Nimrod-region genes is beneficial for the organism.



Figure 4: The nim region in Drosophila melanogaster



3) Cell-mediated immunity of the honey bee, Apis mellifera

We carry out comparative studies on the cell-mediated immunity of an economically important social insect, the honeybee Apis mellifera, on the basis of the knowledge gained in Drosophila. We use two approaches. The first one is a directed system where we take immune-associated-hits from Drosophila and express genes using the Baculovirus system in order to make antibodies to the expressed proteins, both monoclonal and polyclonal. The antibodies will be tested in hemocytes and the hematopoietic compartments in all developmental stages, as well as in the different casts, and their possible involvement in phagocytosis will also be studied. The second one is an undirected approach. Antibodies are raised and tested on hemocytes of different casts and developmental stages, and the expression of the identified markers is further studied with respect to expression pattern. We combine the marker analysis with functional assays such as phagocytosis and the encapsulation reaction.



Figure 5: Apis mellifera hemocyte subsets, as distinguished by antibodies


Selected publications

Kurucz, E., Zettervall, C.-J., Sinka, R., Vilmos, P., Pivarcsi, A., Ekengren, S., Hegedűs, Z., Ando, I. and Hultmark, D. (2003). Hemese, a hemocyte-specific transmembrane protein affects the cellular immune response in Drosophila. Proc. Natl. Acad. Sci. U.S.A. 100: 2622-2627.

Vilmos, P., Nagy, I., Kurucz, É., Hultmark, D., Gateff, E., Ando, I. (2004). A rapid rosetting method for separation of hemocyte sub-populartions in Drosophila melanogaster. Dev. Comp. Immunol, 28: 555-563.

Sinenko, S.A., Kim, E.K., Wynn, R., Manfruelli, P., Ando, I., Wharton, K., Perrimon, N. and Mathey-Prevot, B. (2004). Yantar, a conserved arginine-rich protein is involved in Drosophila hemocyte development. Dev. Biol. 273: 48-62.

Zettervall, C.-J., Anderl, I., Williams, M.J., Palmer, R., Kurucz, E., Ando, I. and Hultmark, D. (2004). A direct screen for genes involved in Drosophila blood cell activation. Proc. Natl. Acad. Sci. U.S.A. 101: 14192-14197.

Markus, R., Kurucz, E., Rus, F. and Ando, I. (2005). Sterile wounding is a minimal and sufficient trigger for a cellular immune response in Drosophila melanogaster. Immunol Lett. 101(1): 108-111.

Williams, M.J., Ando, I. and Hultmark, D. (2005). Drosophila melanogaster Rac2 is necessary for a proper cellular immune response. Genes Cells. 10(8): 813-823.

Rus, F., Kurucz, E., Markus, R., Sinenko, S.A., Laurinyecz, B., Pataki, C., Gausz, J., Hegedus, Z., Udvardy, A., Hultmark, D. and Andó, I. (2006). Expression pattern of Filamin-240 in Drosophila blood cells. Gene Expr. Patterns. 6(8): 928-934.

Kurucz, E., Váczi, B., Márkus, R., Laurinyecz, B., Vilmos, P., Zsámboki, J., Csorba, K., Gateff, E., Hultmark, D. and Ando, I. (2007). Definition of Drosophila hemocyte subsets by cell-type specific antigens. Acta Biol. Hung. 58: 95-111.

Kurucz, É., Márkus, R., Zsámboki, J., Medzihradszky, K.F., Darula, Zs., Vilmos, P., Udvardy, A., Krausz, I., Lukacsovich, T., Gateff, E., Zettervall, C-J., Hultmark, D. and Andó, I. (2007). Nimrod, a Putative phagocytosis receptor with EGF repeats in Drosophila Plasmatocytes. Current Biology, 17(7): 649-654.

Sipos, B., Somogyi, K., Andó, I. and Pénzes, Zs. (2008). 2prhd: A tool to study the patterns of repeat evolution. BMC Bioinformatics. 18: 9:27.

Somogyi, K., Sipos, B., Pénzes, Zs., Kurucz, É., Zsámboki, J., Hultmark, D. and Andó, I. (2008). Evolution of genes and repeats in the nimrod superfamily. Mol. Biol. Evol. 25(11): 2337–2347.

Márkus, R., Laurinyecz, B., Kurucz, E., Honti, V., Bajusz, I., Sipos, B., Somogyi, K., Kronhamn, J., Hultmark, D. and Andó, I. (2009). Sessile hemocytes as a hematopoietic compartment in Drosophila melanogaster. Proc. Natl. Acad. Sci. U.S.A. 106(12): 4805-4809.