T cellB cell collaboration in the immune response to infection Essay

T cellB cell collaboration in the immune response to infection - Essay Example It is referred to as "non-specific" because it generally attempts to stop the spread of all types of invaders. (Kuby, 1996) The latter type consists of two categories: cell-mediated immunity and antibody-mediated (humoral) immunity. It is the stronger one of the two types but takes several hours or even days to become fully activated. It is referred to as "specific" because it responds differently to every other foreign pathogen. (Hariharan, 2006) Lymphocytes, a class of White Blood Cells, are a vital part of the acquired immune system, being responsible for the whole reaction. They are produced in the primary lymphoid organs and then migrate to the secondary lymphoid organs where they recognize antigens of foreign bodies by the help of membrane receptors specific to the antigens. Two major classes of lymphocytes take part in the acquired immunity: B-Cells (B lymphocytes) and T-Cells (T lymphocytes). (Alberts, Bray, Lewis, Raff, Roberts, Watson, 1994), (Linnemeyer, 1993) Precursors of T-cells originate in the foetal liver and yolk sac during the embryonic life, and migrate to the bone marrow after birth. The stem cells then enter the thymus by chemo taxis and develop into T-cells which are later specialized into CD4+ (helper) cells or CD8+ (cytotoxic) cells. (UNC-SOM, 2004) Maturation On entering the thymus, T-cell precursors (prothymocytes) develop into T-cells that indicate both CD4 and CD8 molecules on their membranes and then later continue to indicate either CD4 or CD8 molecules. The cells having antigen receptors for self proteins are destroyed by aptosis (programmed cell death). This prevents autoimmunity. On the other hand, the cells having antigen receptors that do not react with self MHC proteins are also killed as this causes the definite selection of T-cells that do react with MHC proteins. (Stadnyk, 2007) Functions of the MHC proteins include positive selection of T-cells as well as presentation of foreign body antigens to them. (NIAID, 2003) General Function The Helper T-cells activate lymphocytes called macrophages and other T-cells involved in the immune response, and aid B-cells in producing antibodies by alerting them and determining the type of antibody to be produced. (NIAID, 2003) 2) B-Cells: Origin Precursors of B-cells migrate from the foetal liver to the bone marrow where they remain and undergo maturation throughout the adult life. They do not require thymus for their development. (Levinson, 2004) Maturation Development of B-cells takes place in two phases: antigen-independent phase & antigen-dependent phase. In the 1st phase, stem cells of the marrow differentiate into B-lineage and progenitor B-cells. The progenitor B-cells proliferate into precursor B-cells which requires the microenvironment supplied by the surrounding stroma. Cells of the stroma release numerous cytokines, most importantly IL-7, which help in the maturation process. Further

Multicultural Education Improvement Research Paper

Multicultural Education Improvement - Research Paper Example Banks (1994) identifies five dimensions of multicultural education.   The first of these dimensions are â€Å"content integration† which is a technique by which educators ensure that teaching reflects cultural diversity (Banks 1994, p. 4). An example is to emphasize contributions in the field of study by diverse cultural heroes. Secondly, educators utilize â€Å"knowledge construction† which informs students how perspectives are influenced by â€Å"conclusions reached within that discipline† (Banks 1994, p. 5).   The third dimension of multicultural education is referred to by Banks (1994) as â€Å"prejudice reduction† which helps students to form objective views of diverse groups (p. 5). The fourth dimension is â€Å"equitable pedagogy† which attempts to alter classroom instructions that all students among different cultural groups perform academically.   The final dimension is â€Å"empowering school culture and social structure† whic h focuses on the environment within the school and ensuring that it supports diversity among the student body. Multicultural education can be defined as education strategies designed to accommodate teaching and learning for diverse cultures.   The idea is to provide for fostering pluralism among races, cultures and classes.   Theoretically at least, if students are subjected to multicultural education that is properly integrated into teaching and learning processes, attachment and engagement should improve.   ... 5). The third dimension of multicultural education is referred to by Banks (1994) as â€Å"prejudice reduction† which helps students to form objective views of diverse groups (p. 5). The fourth dimension is â€Å"equitable pedagogy† which attempts to alter classroom instructions that all students among different cultural groups perform academically (Banks 1994, p. 5). The final dimension is â€Å"empowering school culture and social structure† which focuses on the environment within the school and ensuring that it supports diversity among the student body (Banks 1994, p. 5). Multicultural education can be defined as education strategies designed to accommodate teaching and learning for diverse cultures. The idea is to provide for fostering pluralism among races, cultures and classes. Theoretically at least, if students are subjected to multicultural education that is properly integrated into teaching and learning processes, attachment and engagement should improv e. Ukpokodu (2009) informs that if multicultural education focuses on transformative learning, students of all races, cultures and classes transform their way of thinking and their perspectives and attitudes to more democratic and objective ways of thinking (2). Arguably, students become more responsible citizens and want to be productive citizens. As Banks (2008) argues, responsible citizenship can be hampered and can be lost on minorities when they are forced to detach themselves from their own cultures and languages (p. 130). Therefore by virtue of transformative learning under the auspices of effective multicultural education, students can be expected to become more engaged and attached to school, as they are not forced to become detached from their own cultures, races and classes. To