Mechanisms of basophil recruitment in allergic diseases

Parallelized Immunomagnetic Isolation of Basophils Directly from Whole Blood

Basophils are the rarest circulating white blood cells (WBCs), but they play important roles in allergic disorders and other diseases. To enhance diagnostic capabilities, it would be desirable to isolate and analyze basophils efficiently from small blood samples. In 100 μL of whole blood, there are typically ~103 basophils, outnumbered by ~105 WBCs and ~108 red blood cells (RBCs). Basophils' low abundance has therefore presented a significant challenge in their isolation from whole blood. Conventional in-bulk basophil isolation methods require lengthy processing steps and cannot work with small volumes of blood. Here we report a parallelized integrated basophil isolation device (pi-BID) for the negative immunomagnetic selection of basophils directly from 4 samples of 100 μL of whole blood, in parallel, within 14 minutes including sample preparation time. The pi-BID interfaces directly with standard sample tubes, and uses a single pressure source to drive the flow in parallel microfluidic channels. Compared with conventional in-bulk basophil isolation, the pi-BID is >3× faster, and has higher purity (~93%) and similar recovery (~67%). Compared with other microfluidic devices for the immunomagnetic isolation of WBC sub-types, our pi-BID achieves 10× higher enrichment of target cells from whole blood, with no prior removal of RBCs necessary.

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

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.

Cerivastatin and atorvastatin inhibit IL-3-dependent differentiation and IgE-mediated histamine release in human basophils and downmodulate expression of the basophil-activation antigen CD203c/E-NPP3

Recent data suggest that the statins, apart from their lipid-lowering activity, exhibit profound anti-inflammatory effects. Basophils are major proinflammatory effector cells in diverse pathologic reactions. We have examined the in vitro effects of five different statins on primary human basophils, their progenitors, and the basophil cell line KU-812. Preincubation of blood basophils with cerivastatin or atorvastatin (0.1-100 microM) for 24 h reduced their capacity to release histamine on immunoglobulin E (IgE)-dependent stimulation in a dose-dependent manner. These statins also inhibited IgE-dependent up-regulation of the basophil-activation antigen CD203c. Moreover, both statins suppressed interleukin-3-induced differentiation of basophils from their progenitors as well as (3)H-thymidine uptake in KU-812 cells. All inhibitory effects of cerivastatin and atorvastatin were reversed by mevalonic acid (200 microM). The other statins tested (lovastatin, simvastatin, pravastatin) did not show significant inhibitory effects on basophils. Together, these data identify cerivastatin and atorvastatin as novel inhibitors of growth and activation of human basophils.

Hypersensitivity disorders in horses

Hypersensitivity is an exaggerated immunologic response to a foreign agent that results in inflammation and organ dysfunction. Hypersensitivity disorders are broadly divided into antibody-mediated and T-cell-mediated reactions. The inflammatory pathways that result in disease are initiated in an antigen-specific manner through Fab portions of antibodies or the T-cell receptor, causing the up-regulation of effector mechanisms designed to clear the offending agent. Effector mechanisms include the generation of inflammatory chemicals such as cytokines and chemokines and the attraction of leukocytes and potentiation of their function. This article reviews current concepts in the immunopathogenesis of hypersensitivity disorders and demonstrates these mechanisms as they apply to equine disease.