Samples were viewed at 6006 magnification with a Nikon TE300 inverted microscope. Microscopy was performed on an Olympus IX-70 or IX-80 microscope equipped with a cooled CCD camera. For live imaging, samples were loaded onto a stage heated to 37uC by a fan and antibody staining was not used. Media was changed every ,60 minutes during long time sequences. Images were collected and color-combined using Metamorph software (Universal Imaging). Large collections of photomicrographs were used for counting cytosolic contents; each graph represents .100 bacteria or liposomes, and three trials for each time point. Figures were compiled in Adobe Photoshop software. Bars are SEM (standard error of mean), where n = 3. Definition of Mafa-A and -B haplotypes in pedigreed cynomolgus macaques (Macaca fascicularis) The major histocompatibility complex (MHC) class I B gene/allelic repertoire was investigated in a pedigreed population of cynomolgus macaques of mixed Indonesian/Malaysian origin. The Mafa-B alleles detected in this cohort are mostly specific for a given geographic area, and only a small number of alleles appears to be shared with other populations. This suggests the fast evolution of Mafa-B alleles due to adaptation to new environments. In contrast to humans, the B locus in Old World monkeys displays extensive copy number variation. The Mafa-B and previously defined -A gene combinations segregate in families and thus allowed the definition of extended haplotypes. In many cases it was possible to assign a particular Mafa-I allele to one of these Mafa-A/B haplotypes as well. The presence of a large number of stable haplotypes in this cohort of animals, which was pedigreed for up to eight generations, looks promising for developing discriminative MHC typing tools that are less cumbersome. Furthermore, the discovery of 53 unreported Mafa-B sequences expands the lexicon of alleles significantly, and may help in understanding the complex organisation of the macaque B region. The cynomolgus macaque (Macaca fascicularis), also known as the crab-eating or long-tailed macaque, is widely used as an animal model in biomedical studies. Currently this species is applied as often as the commonly used rhesus macaque (Macaca mulatta). Cynomolgus monkeys are used as models for infectious diseases, such as AIDS, SARS and tuberculosis, as well as for transplantation research (McAuliffe et al. 2004; Wiseman et al. 2007; Aoyama et al. 2009; Mee et al. 2009; Reed et al. 2009 ). Owing to use of macaques in immune-related research, thorough investigations of their major histocompatibility complexes (MHC) are required. The MHC represents a multigene family in which the proteins play a key role in the generation of adaptive immune responses in vertebrate species. The class I and II genes of the MHC display abundant polymorphism that has a profound impact on features such as disease susceptibility, organ transplantation, and reproduction success.