Clinical and Laboratory Profile of Patients With Anaphylaxis to Fire Ant Venom (Solenopsis Sp) Under Specific Subcutaneous Immunotherapy.

Anaphylaxis to fire ant venoms (Solenopsis sp) is a significant cause of systemic allergic reaction caused by Hymenoptera stings in children. There are only a few reports about the safety and efficacy of specific immunotherapy. We aim evaluate clinical characteristics, IgE and IgG4 specific responses of patients undergoing immunotherapy with a whole-body extract of Solenopsis sp after one year of the maintenance phase. Thirty-three patients were enrolled due to anaphylaxis by fire ant venom (Solenopsis sp) and underwent specific venom immunotherapy. They were assessed at baseline and one year after the beginning of the maintenance phase for skin test; specific IgE and IgG4 antibodies to fire ant venom; tryptase. All patients included presented a severe anaphylactic reaction. Although two patients (6.25%) presented a tryptase level higher than 11.4 ug/ml, systemic mastocytosis was ruled out. There was no relationship between the severity of the reaction with gender, tryptase level, atopy, previous reactions, concentration of the allergen in the skin test or specific IgE level. There was an increase of the specific IgG4/IgE ratio between the two time points. Reactions were local, with only two mild systemic reactions during the build-up phase. Twenty patients had accidental stings during immunotherapy, with 3 presenting only urticaria. This study is unprecedented in evaluating clinical and laboratory data in the fire ant immunotherapy. Our results show that after one year of the maintenance phase, patients did not develop any severe reaction with only a few mild reactions and presented a significant production of specific IgG4.

TOXIC AND IMMUNE ALLERGIC RESPONSES OF ANT VENOM TOXINS: A REVIEW

Present review article explains ant venom components and its allergic and biological effects in man and animals. Red ants or small fire ants secrete and inject venom very swiftly to defend their nest against predators, microbial pathogens, and competitors and to hunt the prey. Ant venom is a mixture of various organic compounds, including peptides, enzymes, and polypeptide toxins. It is highly toxic, allergic, invasive and venomous. It imposes sever paralytic, cytolytic, haemolytic, allergenic, pro-inflammatory, insecticidal, antimicrobial, and pain-producing pharmacologic activities after infliction. Victims show red ring-shaped allergic sign with regional swelling marked with intense pain. Ant venom also contains several hydrolases, oxidoreductases, proteases, Kunitz-like polypeptides, and inhibitor cysteine knot (ICK)-like (knottin) neurotoxins and insect defensins. Ant venom toxins/proteins generate allergic immune responses and employ eosinophils and produce Th2 cytokines, response. These compounds from ant venom could be used as a potential source of new anticonvulsants molecules. Ant venoms contain many small, linear peptides, an untapped source of bioactive peptide toxins. The remarkable insecticidal activity of ant venom could be used as a promising source of additional bio-insecticides and therapeutic agents.

Fire Ant Venom Alkaloids: Possible Control Measure for Soilborne and Foliar Plant Pathogens

The purpose of this study was to evaluate fire ant venom alkaloids and an alarm pheromone analog against several plant pathogens, including Botrytis cinerea, Fusarium oxysporum, Phytophthora nicotianae, P. cryptogea, Pseudomonas syringae, Phytopythium citrinum, Rhizoctonia solani, Sclerotonia rolfsii, Xanthomonas axonopodis, and X. campestris. All pathogens were tested against red imported fire ant venom alkaloid extract and alarm pheromone compound for growth inhibition in in vitro assay. The venom alkaloid extract inhibited fungal and oomycete pathogens. Neither of the treatments were effective against bacterial pathogens. Three soilborne pathogens, P. nicotianae, R. solani, F. oxysporum, and one foliar pathogen, B. cinerea were selected for further in-vivo assays on impatiens (Impatiens walleriana ‘Super Elfin XP violet’). Total plant and root weight were higher in venom alkaloid treated plants compared to an inoculated control. The venom alkaloid treatment reduced damping-off, root rot severity, and pathogen recovery in soilborne pathogen inoculated plants. Similarly, venom alkaloid reduced Botrytis blight. However, higher venom rates caused foliar phytotoxicity on plants. Therefore, additional work is needed to evaluate rates of venom alkaloids or formulations to eliminate negative impacts on plants. Overall, these results suggest that red imported fire ant venom alkaloids may provide a basis for new products to control soilborne and foliar plant pathogens.

Composition and Acute Inflammatory Response from Tetraponera rufonigra Venom on RAW 264.7 Macrophage Cells

Tetraponera rufonigra (Arboreal Bicoloured Ant) venom induces pain, inflammation, and anaphylaxis in people and has an increased incident in Southeast Asia regions. The bioactive components and mechanism of action of the ant venom are still limited. The aim of this research was to identify the protein composition and inflammatory process of the ant venom by using RAW 264.7 macrophage cells. The major venom proteins are composed of 5’ nucleotidase, prolyl endopeptidase-like, aminopeptidase N, trypsin-3, venom protein, and phospholipase A2 (PLA2). The venom showed PLA2 activity and represented 0.46 μg of PLA2 bee venom equivalent/μg crude venom protein. The venom induced cytotoxic in a dose- and time-dependent manner with IC20 approximately at 4.01 µg/mL. The increased levels of COX-2 and PGE2 were observed after 1 h of treatment correlating with an upregulation of COX-2 expression. Moreover, the level of mPGES-1 expression was obviously increased after 12 h of venom induction. Hence, our results suggested that the induction of COX-2/mPGEs-1 pathway could be a direct pathway for the ant venom-induced inflammation.

Avoiding being stung or bitten – prey capture behaviors of the ant-eating Texas horned lizard (Phrynosoma cornutum)

ABSTRACT Horned lizards (Phrynosoma) are specialized predators, including many species that primarily feed on seed harvester ants (Pogonomyrmex). Harvester ants have strong mandibles to husk seeds or defensively bite, and a venomous sting. Texas horned lizards possess a blood plasma factor that neutralizes harvester ant venom and produce copious mucus in the pharynx and esophagus, thus embedding and incapacitating swallowed ants. We used high-speed video recordings to investigate complexities of their lingual prey capture and handling behavior. Lizards primarily strike ants at their mesosoma (thorax plus propodeum of abdomen). They avoid the head and gaster, even if closer to the lizard, and if prey directional movement is reversed. Orientation of captured ants during retraction is with head first (rostral), thus providing initial mucus coating of the mandibles. Prey capture accuracy and precise handling illustrates the specificity of adaptations of horned lizards in avoiding harm, and the challenges lizards face when feeding on dangerous prey.