L3L4ES antigen and secretagogues induce histamine release from porcine peripheral blood basophils after Ascaris suum infection

Abstract

The aim of this paper was to investigate the role of porcine basophils in protective immunity. Experimental pigs were infected with 10(3) Ascaris suum eggs daily for 21 days. Control pigs were maintained helminth-free. Circulating porcine basophils were isolated from the anticoagulated whole blood of A. suum-infected and noninfected pigs by dextran (4.5%) sedimentation of erythrocytes or by the centrifugation of dextran-isolated leukocytes through discontinuous Percoll gradients. Results showed that 2.2% of the isolated leukocytes, stained with May-Grunwald Giemsa, were basophils. Each basophil from infected pigs contained 1.30 x 10(-2) to 1.20 x 10(-1) pg of histamine. Peripheral blood basophils (PBBs) from infected swine released 49% specific histamine when induced with A. suum-derived antigen (L3L4ES), 55% with anti-immunoglobulin G, and 62% with calcium ionophore A23l87. During A. suum infection, the number of isolated basophils and histamine levels peaked at 14 to 21 days postinfection and then showed a significant decrease. Percent-specific histamine released from PBBs by infected swine was significantly greater than that released by control pigs. The L3L4ES antigen and secretagogues effectively induced specific/nonspecific histamine release from PBBs and should facilitate future investigations of porcine basophils.

The Intestinal Expulsion of the Roundworm Ascaris suum Is Associated with Eosinophils, Intra-Epithelial T Cells and Decreased Intestinal Transit Time

“…Mast cells and basophils have previously been associated with A. suum infections [18], [30], [31]. Repeated infections induced blood basophilia and intestinal mastocytosis, and these cells responded to stimulation with L3 or L4 secretory antigens by releasing histamine [30], [31].…”

“…Repeated infections induced blood basophilia and intestinal mastocytosis, and these cells responded to stimulation with L3 or L4 secretory antigens by releasing histamine [30], [31]. The maximum histamine release occurred between 14 and 21 days after daily exposure, therefor it has been suggested that these cells played an important role during self-cure [32].…”

“…The maximum histamine release occurred between 14 and 21 days after daily exposure, therefor it has been suggested that these cells played an important role during self-cure [32]. However, only basophils or mast cells that had previously been exposed to Ascaris released histamine following contact with L3 or L4 secretory antigens [30], [31]. We also show here that in contrast to experiments with repeated infections, mast cells were not induced in the small intestine after primary infections, suggesting that basophils or mast cells may only play a role in protection against secondary infections.…”

A Role for Eosinophils in the Intestinal Immunity against Infective Ascaris suum Larvae

“…They are also the primary source of histamine. It was previously shown that mast cells and basophils from repeatedly infected animals released histamine after contact with Ascaris secretory antigens [26], [27]. Histamine has various functions.…”

The immune response to parasitic helminths of veterinary importance and its potential manipulation for future vaccine control strategies

“…However, other studies have reported in vitro mast cell degranulation in response to A. suum antigens (Ashraf et al 1988) and an increased expression of mast cell tryptase in the ileum, liver and bronchial-alveolar lavage fluid (BAL) in vivo (Dawson et al 2005), thus indicating an important immunological role for mast cells during A. suum infection of pigs. Porcine basophils also degranulate in response to A. suum L3 and L4 antigens in vitro and histamine degranulation by basophils in vivo is at a maximum between 14 and 21 days pi (Uston et al 2007), which may also indicate a role for basophils in the 'self-cure' response, possibly by increasing vascular permeability and effector cell migration into the intestine. Dawson et al (2005) also reported a strongly skewed Th2 response (elevated IL-4 and IL-13) in the ileum and BAL of A. suum-infected pigs with no significant elevation of Th1 cytokines (IFN-γ and TNF-α) in these same tissues and fluid.…”