Banca de DEFESA: HALLISON MOTA SANTANA

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : HALLISON MOTA SANTANA
DATE: 20/10/2025
TIME: 08:00
LOCAL: Sala Virtual Remota (Microsoft TEAMS) https://bit.ly/DefDoc_HallisonSantana_PGBIOEXP
TITLE:

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KEY WORDS:

Snake Venoms; Bothrops; Camelids; IL-1β; Polyclonal Serum.

PAGES: 117
BIG AREA: Ciências Biológicas
AREA: Biologia Geral
SUMMARY:

In Latin America, snakebite envenomation is considered both an occupational and a
neglected disease. Recent studies estimate that the number of snakebite incidents
involving venomous snakes worldwide exceeds 420,000 annually, with approximately
20,000 resulting in death. In Brazil, most envenomation cases are caused by snakes
of the Bothrops genus, which comprises more than 60 species distributed across the
country. While many of the systemic effects of snake venom are neutralized by
antivenom therapy, local effects—such as myonecrosis, dermonecrosis, pain, and
edema are not fully mitigated. One of the key protein classes responsible for triggering
the severe local inflammatory response is snake venom phospholipases A₂ (svPLA₂s),
which contribute to cytotoxic and myotoxic damage in tissues. Camelid hyperimmune
serum contains antibodies that lack light chains, known as heavy-chain antibodies
(HcAbs; IgG2 and IgG3), with a molecular weight of approximately 90 kDa. These
antibodies contain a single antigen-recognition domain of the heavy chain, termed
VHH or nanobody. VHH domains exhibit lower immunogenicity, enhanced tissue
permeability, and greater resistance to pH and temperature variations, presenting
biotechnological potential for use as therapeutic agents to complement conventional
antivenom therapy. HcAbs from Lama glama were purified from hyperimmune serum
obtained following immunization with the whole venom and phospholipases A₂ from
Bothrops jararacussu venom (vBj). IgG purification was performed using A and G
Sepharose columns. Yields of IgG1, IgG2, and IgG3 were approximately 4 mg/mL, 1
mg/mL, and 200 μg/mL, respectively. An experimental treatment was subsequently
conducted in Swiss mice (18-20 g), in which 7 μg of HcAbs were administered
following intramuscular injection of 25 μg of vBj into the gastrocnemius muscle. Posttreatment
blood samples were collected, and plasma was analyzed for biomarkers of
muscle damage (creatine kinase - CK) and cytotoxicity (lactate dehydrogenase -
LDH), both of which showed significant reductions compared to the envenomated,
untreated group. Similarly, the cardiac damage marker CK-MB was significantly
reduced. The marker for acute hepatic injury (aspartate aminotransferase - AST) also
decreased significantly relative to the untreated control, whereas the marker for chronic
liver injury (alanine aminotransferase - ALT) remained unchanged across all groups.
To evaluate the local inflammatory response, the release of the cytokine IL-1β and the
protein expression of the NLRP3 sensor component of the inflammasome complex
were measured. IL-1β and NLRP3 were highly expressed in the muscle tissue of
animals inoculated with vBj, however, a significant decrease was observed after
treatment with HcAbs. Treatment with HcAbs proved promising, as it was able to
reduce tissue damage in an experimental animal model of vBj envenomation,
highlighting the importance of new therapeutic approaches as an adjuvant to
antivenom therapy in snakebite envenomation.

COMMITTEE MEMBERS:
Externa à Instituição - LUCILENE DELAZARI DOS SANTOS - UNESP
Externa à Instituição - SONIA APARECIDA DE ANDRADE CHUDZINSKI
Externo à Instituição - LEONARDO DOS SANTOS CORRÊA AMORIM
Externo à Instituição - EDUARDO LANI VOLPE DA SILVEIRA - USP
Presidente - 1726461 - JULIANA PAVAN ZULIANI TRENCH DE SOUZA