Frozen Cord Blood Hematopoietic Stem Cells Differentiate into Higher Numbers of Functional Natural Killer Cells In Vitro than Mobilized Hematopoietic Stem Cells or Freshly Isolated Cord Blood Hematopoietic Stem Cells

Adoptive natural killer (NK) cell therapy relies on the acquisition of large numbers of NK cells that are cytotoxic but not exhausted. NK cell differentiation from hematopoietic stem cells (HSC) has become an alluring option for NK cell therapy, with umbilical cord blood (UCB) and mobilized peripheral blood (PBCD34⁺) being the most accessible HSC sources as collection procedures are less invasive. In this study we compared the capacity of frozen or freshly isolated UCB hematopoietic stem cells (CBCD34⁺) and frozen PBCD34⁺ to generate NK cells in vitro. By modifying a previously published protocol, we showed that frozen CBCD34⁺ cultures generated higher NK cell numbers without loss of function compared to fresh CBCD34⁺ cultures. NK cells generated from CBCD34⁺ and PBCD34⁺ expressed low levels of killer-cell immunoglobulin-like receptors but high levels of activating receptors and of the myeloid marker CD33. However, blocking studies showed that CD33 expression did not impact on the functions of the generated cells. CBCD34⁺-NK cells exhibited increased capacity to secrete IFN-γ and kill K562 in vitro and in vivo as compared to PBCD34⁺-NK cells. Moreover, K562 killing by the generated NK cells could be further enhanced by IL-12 stimulation. Our data indicate that the use of frozen CBCD34⁺ for the production of NK cells in vitro results in higher cell numbers than PBCD34⁺, without jeopardizing their functionality, rendering them suitable for NK cell immunotherapy. The results presented here provide an optimal strategy to generate NK cells in vitro for immunotherapy that exhibit enhanced effector function when compared to alternate sources of HSC.     

WASp in immune-system organization and function

The regulation of many immunological events depends on systems that mediate dynamic actin reorganization in response to signals from the cell membrane. The Wiskott-Aldrich syndrome protein (WASp) is the founding member of a family of proteins that have emerged as crucial effectors of Rho GTPases and activators of the cytoskeletal-organizing complex Arp2/3. Now, WASp has been shown to be intimately involved in many pathways that influence the function of the immune system. Disturbances in these systems result in the complex immunodysregulation of Wiskott-Aldrich syndrome.     

Ontogeny and Sexual Dimorphism of <Emphasis Type="Italic">Glyptotherium texanum</Emphasis> (Xenarthra,Cingulata) from the Pliocene and Pleistocene (Blancan and Irvingtonian NALMA) of Arizona,New Mexico,and Mexico

North American glyptodonts originated from South American ancestors during the Great American Biotic Interchange no later than early Blancan North American Land Mammal Age (NALMA). A substantial expansion in population samples from the late Blancan 111 Ranch fauna of southeastern Arizona, several late Blancan faunas in New Mexico, and the early Blancan–Irvingtonian faunas of Guanajuato, Mexico, permit, analysis of sexual dimorphism and ontogeny of Glyptotherium texanum Osborn, 1903. Growth of carapacial osteoderms was allometric, including changes of the external sculpturing. Overall anatomy of the carapace changed with growth, with development of distinctive pre-iliac and post-iliac regions in lateral profile of adults. Skulls of adults possess a unique boss on the anterior surface of the descending process of the zygomatic arch that is not present in juveniles. Sexual dimorphism involves differences in anatomy of lateral and posterior osteoderms. Glyptotherium arizonae Gidley, 1926, is a junior synonym of G. texanum. The temporal distribution of G. texanum extends from early Blancan NALMA to Irvingtonian NALMA, with geographical distribution from Central America and Mexico to southern United States.     

Dendritic cells: the bare bones of immunity

Dendritic cells are specialized antigen-presenting cells, critical for initiating and regulating immune responses. Two new studies demonstrate the importance of coordinated cytoskeletal regulation for their normal function.     

Role of WASP in cell polarity and podosome dynamics of myeloid cells

The integrin-dependent migration of myeloid cells requires tight coordination between actin-based cell membrane protrusion and integrin-mediated adhesion to form a stable leading edge. Under this mode of migration, polarised myeloid cells including dendritic cells, macrophages and osteoclasts develop podosomes that sustain the extending leading edge. Podosome integrity and dynamics vary in response to changes in the physical and biochemical properties of the cell environment. In the current article we discuss the role of various factors in initiation and stability of podosomes and the roles of the Wiskott Aldrich Syndrome Protein (WASP) in this process. We discuss recent data indicating that in a cellular context WASP is crucial not only for localised actin polymerisation at the leading edge and in podosome cores but also for coordination of integrin clustering and activation during podosome formation and disassembly.     

Gene therapy for severe combined immune deficiency

Infants born with severe combined immune deficiencies are prone to life-threatening infections and, without treatment, do not survive beyond the first year of life. Haematopoietic stem cell transplantation from a fully matched donor offers the possibility of cure. In the absence of a suitable matched donor, haploidentical transplants from a parental donor may be undertaken, but these are associated with more complications and lower success rates. Recently, an alternative therapeutic option based on retroviral gene delivery has been used to correct X-linked severe combined immune deficiency (SCID-X1) and adenosine deaminase deficiency. Clinical trials have established that in situations where ex vivo gene transfer into haematopoietic progenitor cells confers a strong selective advantage, the procedure is a feasible alternative to haploidentical transplantation, with favourable kinetics of immune reconstitution.