Tissue and Cell 37 (2005) 193–202 Cytochemical and functional characterization of blood and inflammatory cells from the lizard Ameiva ameiva Sanny O. Alberio a , Jose A. Diniz b , Edilene O. Silva c , Wanderley de Souza d , Renato A. DaMatta e, ∗ a Departamento de Fisiologia, Universidade Estadual do Par´ a, 66887-670 Bel´ em, PA, Brazil b Unidade de Microscopia Eletrˆ onica, Instituto Evandro Chagas, 66001-000 Bel´ em, PA, Brazil c Laborat´ orio de Parasitologia, Centro de Ciˆ encias Biol ´ ogicas, Universidade Federal do Par´ a, 66075-110 Bel´ em, PA, Brazil d Laborat´ orio de Ultraestrutura Celular Hertha Meyer, Instituto de Biof´ ısica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, 21949-900 Rio de Janeiro, RJ, Brazil e Laborat´ orio de Biologia Celular e Tecidual, Centro de Biociˆ encias e Biotecnologia, Universidade Estadual do Norte Fluminense, 28015-620, Av. Alberto Lamego 2000, Horto, 28013-600 Campos dos Goytacazes, RJ, Brazil Received 21 May 2004; received in revised form 22 December 2004; accepted 30 December 2004 Available online 16 March 2005 Abstract The fine structure and differential cell count of blood and coelomic exudate leukocytes were studied with the aim to identify granulocytes from Ameiva ameiva, a lizard distributed in the tropical regions of the Americas. Blood leukocytes were separated with a Percoll cushion and coelomic exudate cells were obtained 24 h after intracoelomic thioglycollate injection. In the blood, erythrocytes, monocytes, thrombocytes, lymphocytes, plasma cells and four types of granulocytes were identified based on their morphology and cytochemistry. Types I and III granulocytes had round intracytoplasmic granules with the same basic morphology; however, type III granulocyte had a bilobued nucleus and higher amounts of heterochromatin suggesting an advance stage of maturation. Type II granulocytes had fusiformic granules and more mitochondria. Type IV granulocytes were classified as the basophil mammalian counterpart based on their morphology and relative number. Macrophages and granulocytes type III were found in the normal coelomic cavity. However, after the thioglycollate injection the number of type III granulocyte increased. Granulocytes found in the coelomic cavity were related to type III blood granulocyte based on the morphology and cytochemical localization of alkaline phosphatase and basic proteins in their intracytoplasmic granules. Differential blood leukocyte counts showed a predominance of type III granulocyte followed by lymphocyte, type I granulocyte, type II granulocyte, monocyte and type IV granulocyte. Taken together, these results indicate that types I and III granulocytes correspond to the mammalian neutrophils/heterophils and type II to the eosinophil granulocytes. © 2005 Elsevier Ltd. All rights reserved. Keywords: Ameiva ameiva; Reptilian; Leukocytes; Granulocytes; Neutrophils/heterophils; Coelomic exudate cells 1. Introduction Vertebrate blood cells are divided into erythrocytes and leukocytes. Non-mammalian erythrocytes are nucleated and easily recognized morphologically. Thrombocytes, the func- tional analog to mammalian platelets, are also nucleated and, like monocytes and lymphocytes, are more accurately clas- sified by transmission electron microscopy. However, there ∗ Corresponding author. Tel.: +55 22 2726 1694; fax: +55 22 2726 1514. E-mail address: renato@uenf.br (R.A. DaMatta). is marked ambiguity in the classification of non-mammalian granulocytes mainly due to the diverse terminology applied, the lack of functional studies (Meseguer et al., 1994) and morphological similarities to the mammalian granulocytes (Ryerson, 1943; Sypek and Borysenko, 1988). Lately, this terminology has been tentatively standardized and leuko- cyte counts of some reptile species determined by light microscopy (Egami and Sasso, 1988; Work et al., 1998; Alleman et al., 1992, 1999; Stacy and Whitaker, 2000; Harr et al., 2001). Nevertheless, some ambiguity still ex- ists consequent to species differences (Cannon et al., 1996; 0040-8166/$ – see front matter © 2005 Elsevier Ltd. All rights reserved. doi:10.1016/j.tice.2004.12.006