maxadilan-protein--insect and Disease-Models--Animal

Leishmaniasis is an arthropod vectored disease causing considerable human morbidity and mortality. Vaccination remains the most realistic and practical means to interrupt the growing number and diversity of sand fly vectors and reservoirs of Leishmania. Since transmission of Leishmania is achieved exclusively by sand fly vectors via immune-modulating salivary substances, conventional vaccination requiring an unmodified host immune response for success are potentially destined to fail unless immunomodulatory factors are somehow neutralized. Using cationic liposome DNA complexes (CLDC) as an adjuvant system along with Lu. longipalpis sand fly salivary component maxadilan (MAX) as antigen (Ag), we show that mice are protected from the MAX-induced exacerbation of infection with Leishmania major (Lm). The CLDC adjuvant and alum were comparable in terms of lesion induration and decreased parasite burden, however the alum adjuvant imposed more inflammation at the injection site. BALB/c, C3H and C57BL/6 mice vaccinated with MAX-CLDC containing either the full-length MAX or peptides spanning the N- and C-terminal regions of MAX are protected against footpad challenges with Lm co-injected with MAX. When compared to unvaccinated controls, all strains of mice immunized with CLDC containing either peptides encompassing the first 20 N-terminal AA or those spanning the last 15 AA of the C-terminal domain of MAX demonstrated decreased parasite burden after 9 or 18 weeks post challenge with Lm + MAX. MAX-CLDC immunized mice showed increased IFNγ-secreting and decreased IL-4-secreting CD4

Topics: Adjuvants, Immunologic; Alum Compounds; Animals; Cations; CD4-Positive T-Lymphocytes; Disease Models, Animal; DNA; Immunization; Insect Proteins; Leishmania major; Leishmaniasis, Cutaneous; Liposomes; Mice; Mice, Inbred BALB C; Mice, Inbred C3H; Mice, Inbred C57BL; Peptides; Psychodidae; Saliva

We have earlier shown that PACAP-38 decreases neurogenic inflammation. However, there were no data on its receptorial mechanism and the involvement of its PAC1 and VPAC1/2 receptors (PAC1R, VPAC1/2R) in this inhibitory effect. Neurogenic inflammation in the mouse ear was induced by topical application of the Transient Receptor Potential Ankyrin 1 (TRPA1) receptor activator mustard oil (MO). Consequent neurogenic edema, vasodilation and plasma leakage were assessed by measuring ear thickness with engineer's micrometer, detecting tissue perfusion by laser Doppler scanning and Evans blue or indocyanine green extravasation by intravital videomicroscopy or fluorescence imaging, respectively. Myeloperoxidase activity, an indicator of neutrophil infiltration, was measured from the ear homogenates with spectrophotometry. The selective PAC1R agonist maxadilan, the VPAC1/2R agonist vasoactive intestinal polypeptide (VIP) or the vehicle were administered i.p. 15 min before MO. Substance P (SP) concentration of the ear was assessed by radioimmunoassay. Maxadilan significantly diminished MO-induced neurogenic edema, increase of vascular permeability and vasodilation. These inhibitory effects of maxadilan may be partially due to the decreased substance P (SP) levels. In contrast, inhibitory effect of VIP on ear swelling was moderate, without any effect on MO-induced plasma leakage or SP release, however, activation of VPAC1/2R inhibited the increased microcirculation caused by the early arteriolar vasodilation. Neither the PAC1R, nor the VPAC1/2R agonist influenced the MO-evoked increase in tissue myeloperoxidase activity. These results clearly show that PAC1R activation inhibits acute neurogenic arterial vasodilation and plasma protein leakage from the venules, while VPAC1/2R stimulation is only involved in the attenuation of vasodilation.

Topics: Animals; Capillary Permeability; Disease Models, Animal; Ear; Edema; Female; Insect Proteins; Male; Mice; Microcirculation; Mustard Plant; Peroxidase; Plant Oils; Receptors, Pituitary Adenylate Cyclase-Activating Polypeptide, Type I; Receptors, Vasoactive Intestinal Peptide, Type II; Receptors, Vasoactive Intestinal Polypeptide, Type I; Skin Physiological Phenomena; Substance P; Vasoactive Intestinal Peptide; Vasoconstrictor Agents; Vasodilation