**TCTP from** *Loxosceles Intermedia* **(Brown Spider) Venom Contributes to the Allergic and Inflammatory Response of Cutaneous Loxoscelism**

**Marianna Boia-Ferreira 1, Kamila G. Moreno 1, Alana B. C. Basílio 1, Lucas P. da Silva 1, Larissa Vuitika 1, Bruna Soley 2, Ana Carolina M. Wille 3, Lucélia Donatti 1, Katia C. Barbaro 4, Olga M. Chaim 1,5, Luiza Helena Gremski 1, Silvio S. Veiga 1 and Andrea Sen** ff**-Ribeiro 1,\***


Received: 22 August 2019; Accepted: 10 November 2019; Published: 22 November 2019

**Abstract:** LiTCTP is a toxin from the Translationally Controlled Tumor Protein (TCTP) family identified in *Loxosceles* brown spider venoms. These proteins are known as histamine-releasing factors (HRF). TCTPs participate in allergic and anaphylactic reactions, which sugges<sup>t</sup> their potential role as therapeutic targets. The histaminergic e ffect of TCTP is related to its pro-inflammatory functions. An initial characterization of LiTCTP in animal models showed that this toxin can increase the microvascular permeability of skin vessels and induce paw edema in a dose-dependent manner. We evaluated the role of LiTCTP in vitro and in vivo in the inflammatory and allergic aspects that undergo the biological responses observed in Loxoscelism, the clinical condition after an accident with *Loxosceles* spiders. Our results showed LiTCTP recombinant toxin (LiRecTCTP) as an essential synergistic factor for the dermonecrotic toxin actions (LiRecDT1, known as the main toxin in the pathophysiology of Loxoscelism), revealing its contribution to the exacerbated inflammatory response clinically observed in envenomated patients.

**Keywords:** *Loxosceles*; brown spider; TCTP; venom; toxin; HRF
