Proteomic analysis of Ascaridia galli. Identification of immunoreactive proteins in naturally and experimentally infected hens.

Ascaridia galli, intestinal parasite of domestic fowl, is responsible of economic losses in avian exploitations. However, molecular mechanisms that govern avian ascaridiasis remain largely unknown. The aim of the present work was to identify proteins of A. galli recognized by the immune system of naturally and experimentally infected hens, using two-dimensional electrophoresis (2-DE) and mass spectrometry (MS). Sixteen immunoreactive proteins of A. galli were identified. These proteins are mainly related to different metabolic processes, cell motility and binding activities. The timing evolution of this recognition pattern was studied using serum samples from experimentally infected hens, allowing us to observe an early recognition of many of these antigens. Many of them were isoforms from lipid and plasminogen-binding proteins. Moreover, plasminogen-binding activity has been related in other parasites with the facilitation of intra-organic migration, which represents an important fact in avian ascaridiasis. This work represents the first proteomic study of A. galli and could contribute to explain some aspects of parasite/host relationships of avian ascaridiasis.

What is new about animal and human dirofilariosis?

Dirofilaria immitis and D. repens, the causal agents of cardiopulmonary and subcutaneous dirofilariosis, respectively, affect canine, feline and human populations with an increasing incidence in temperate and tropical areas of the world. In the past decade outstanding advances in the knowledge of dirofilariosis have been achieved. Nevertheless, questions such as the impact of climate change in the transmission and distribution of dirofilariosis, as well as a profound evaluation of both the role of Dirofilaria and Wolbachia and the proteins produced by them in the parasite-host relationship have not been fully addressed; therefore there must be milestones in dirofilariosis research in order to design new strategies and tools for the control of this disease.

Identification of immunoreactive proteins from the dog heartworm (Dirofilaria immitis) differentially recognized by the sera from dogs with patent or occult infections.

Heartworm disease caused by Dirofilaria immitis affects canine and feline hosts. Moreover, the parasite can infect humans, causing pulmonary dirofilariosis. Most affected dogs have patent infections with circulating microfilariae in peripheral blood, although infected dogs sometimes develop occult infections characterized by the absence of microfilariae. Microfilaremic infections (mf+) are associated with a predominant Th2-type immune response, whereas a Th1-type response predominates in amicrofilaremic infections (mf-), suggesting a role for this response in the suppression of circulating microfilariae. However, nothing is known about the molecules involved in the immune regulation of these infections. The objective of the present work was to identify the parasite proteins recognized differentially by the immune response of dogs with patent or occult infections, using two-dimensional electrophoresis and mass spectrometry. Nineteen proteins of D. immitis were identified, of which 6 were immunoreactive against serum samples from both mf+ and mf- dogs, while another two groups of 6 and 7 different proteins were differentially recognized by sera from mf+ or mf- dogs, respectively. The results point to the existence of differential antigen recognition in patent and occult infections due to D. immitis. Several proteins that could be involved in the immune regulation of these infections are identified. Additionally, the findings seem to suggest that some antigens of D. immitis, together with Wolbachia antigens, could contribute to the stimulation of the Th1-type response.