Banca de DEFESA: LUDMILA DE JESUS PEREIRA FREITAS

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : LUDMILA DE JESUS PEREIRA FREITAS
DATE: 14/01/2026
TIME: 09:00
LOCAL: Sala Professor Laerte Grisi LQEPV
TITLE:

The immunomodulatory role of Stomoxys calcitrans (L.) saliva

 

KEY WORDS:

vector insects, Immune system, Macrophages, Leishmania infantum, Herpetomonas muscarum.

PAGES: 61
BIG AREA: Ciências Agrárias
AREA: Medicina Veterinária
SUMMARY:

Stomoxys calcitrans (L.), commonly known as the stable fly, is a hematophagous insect of the Diptera order. Its bite causes intense pain in hosts, which are mainly cattle and horses. When present in large numbers, it leads to significant blood loss and stress, resulting in weight loss and a reduction in meat and dairy production, with a major economic impact on livestock activities. During blood feeding, the insect can mechanically transmit various pathogens to the hosts, causing further losses. The saliva of hematophagous insects contains several pharmacologically active molecules that facilitate feeding and can also influence pathogen infection through immunomodulatory effects on their hosts. This immunomodulatory potential can affect different cells of the immune system, including macrophages, cells of the innate immune system that have the potential to secrete diverse cytokines and pro inflammatory mediators. The genus Herpetomonas is a monophyletic group, present on almost all continents, associated with a wide variety of insect species. Recently, the species Herpetomonas muscarum was isolated from S. calcitrans for the first time. Leishmaniases comprise a group of diseases that present four distinct clinical manifestations, depending on the species of the parasite (cutaneous, diffuse cutaneous, mucocutaneous, and visceral). Visceral leishmaniasis, also known as kala-azar, among other regional names, is a systemic and chronic disease. In Brazil, it is caused by the species Leishmania infantum and transmitted by phlebotomine sandfly insect vectors. Visceral leishmaniasis (VL) is known to affect several animal species, such as marsupials, rodents, edentates, and canids, with dogs being the main reservoir and source of human infection in urban areas. Considering the above, the main objective of the present study was to analyze the immunomodulatory effect of the salivary gland extract (SGE) of S. calcitrans on macrophages, as well as to evaluate its effect on L. infantum promastigote forms and H. muscarum opimastigote forms growth, and to assess the cytotoxicity of the salivary gland extract on macrophages, which are the host cells of L. infantum, besides being curccial to iannate response. Possible mechanisms of action of the salivary gland extract were elucidated through the production of nitric oxide and reactive oxygen species, and by evaluating the parasite load of macrophages infected with L. infantum in the presence and absence of fly saliva. The results demonstrated that the salivary gland extract of S. calcitrans does not have cytotoxic potential toward macrophages. The saliva showed no significant effect on binding or phagocytosis in macrophages infected with L. infantum; however, an increase in NO and ROS was observed in macrophages previously treated with saliva, whether they were stimulated with IFN and LPS or not. When the effect of the extract was evaluated directly on L. infantum promastigotes and H. muscarum opimastigotes, proliferation of H. muscarum induction and a lower percentage of survival of L. infantum were observed compared with untreated controls. Our results show an important role of the saliva of S. calcitrans with pharmacological and biotechnical potential in mammals immune system modulation and in the fly own biology.

COMMITTEE MEMBERS:
Presidente - 1792175 - PATRICIA FAMPA NEGREIROS LIMA
Interna - 1335855 - DANIELLE DE OLIVEIRA NASCIMENTO
Interna - 1222756 - DEBORA DECOTE RICARDO DE LIMA
Externo ao Programa - 1674073 - BRUNO GUIMARAES MARINHO - UFRRJExterna à Instituição - POLLYANNA STEPHANIE GOMES
Externa à Instituição - RAÍSSA COUTO SANTANA
Externa à Instituição - PATRICIA DE ALMEIDA MACHADO