Lobed nucleus--more variable, large coarse granules stain blue with basic dye methylene blue .
They play a major role in the allergic response when they release their granules (containing histamine, serotonin, heparin, prostaglandin, etc into the bloodstream following exposure to specific allergens).
Basophils bear Fc receptors for IgE
When an individual is exposed to an allergen, allergen specific IgE is produced. This IgE binds to the surface of basophils
The process of lymphopoiesis (lymphocyte origination and differentiation into functional effector cells) begins in the yolk sac and continues later in life in the thymus gland, liver, spleen, and finally the bone marrow.
monocytes enter the tissues through the process of extravastion.
Changes which occur during this transition: Cells enlarge [5-10x] intracellular organelles increase in number and complexity cells acquire increased phagocytic ability increased secretion of many soluble factors
Macrophages play the following important roles: 1) phagocytosis 2) antimicrobial activity 3) secretion of soluble factors
Macrophages are activated by a variety of stimuli in the course of an immune response. - One of the earliest activating signals comes from chemokines. - Phagocyotosis itself is an important activating stimulus. - Macrophages are further activated by cytokines secreted by T helper cells [IFN-gamma] - and by mediators of the inflammatory response - and by various microbial products (such as LPS)
Dr.B.Victor is a highly experienced postgraduate biology teacher, recently retired from the reputed educational institution St. Xavier’ s College, Palayamkottai, India-627001.Presently HOD of Biotech at Annai Velankanni college, Tholayavattam. K .K Dist
He was the dean of sciences and assistant controller of examinations of St. Xavier’s college.
He has more than 32 years of teaching and research experience and has guided more than 12 Ph. D scholars.
He has taught Immunology and biochemistry to graduate and post graduate students.