Analysis of the role of Dirofilaria repens macrophage migration inhibitory factors in host-parasite interactions

Introduction: Dirofilaria repens is a zoonotic parasitic filarial nematode that infects carnivores and occasionally humans. Knowledge of the host-parasite molecular interactions enabling the parasite's avoidance of the host immune response in subcutaneous dirofilariasis remains limited. Parasitic orthologues of host macrophage migration inhibitory factor (MIF) are molecules potentially involved in this process.

Material and methods: Complementary DNA encoding two D. repens MIF orthologues (rDre-MIF-1 and rDre-MIF-2) was cloned into a pET-28a expression vector. The recombinant proteins were produced in Escherichia coli and purified using affinity nickel chromatography. The reactivity of both recombinant proteins was analysed with infected dog and immunised mouse sera.

Results: Stronger antibody production was induced by rDre-MIF-1 in mice, as evidenced by significantly higher levels of anti-rDre-MIF-1 total IgG, IgG2 and IgE antibodies than of anti-rDre-MIF-2 immunoglobulins. Additionally, a significantly different level of antibodies specific to both proteins was noted between the sera of infected dogs and those of uninfected dogs.

Conclusion: This study is the first attempt to characterise MIF orthologues from the filarial parasite D. repens, which may affect the immune response during infection.