1. The Nature of Blood 12.1 Notes

2. Objectives List the A-B-O antigens and antibodies found in the blood for each of the four blood types: A, B, AB, and O. Understand and describe how whole blood is typed Understand the concept of antigen-antibody interactions and how it is applied to species identification and drug identification

3. Blood A mix of cells, enzymes, proteins, and inorganic substances Plasma – 55% Liquid, primarily water Solid portion 45% Red Blood cells – erythrocytes White blood cells – leukocytes Platelets

4. Serum The pale yellowish liquid that makes up part of the blood clot Pertinent to forensics Red blood cells Blood serum

5. Antigens Chemical structures found on the surface of the red blood cell Impart blood-type characteristics 15 blood antigen systems have been identified More common are ABO and Rh (D)

6. Antigens Type A blood contains A antigens Type B = B antigens Type AB = both A and B antigens Type O = neither A or B Rh+ indicates the presence of D antigen Rh- indicates the absence of D antigen

7. Antibodies Proteins that act against certain antigens Serum-containing antibody = antiserum Considered bivalent Two reactive sites Causes agglutination (clumping)

8. Serology Study of antigen-antibody reactions US distribution of blood types: Type O – 43% Type A – 42% Type B – 12% Type AB – 3%

9. Donor Combinations Blood TypeDonates toReceives from AA, ABA, O BB, ABB, O AB all O only O

10. Antibodies Produced to bind to an invading antigen Different antibodies are produced to attack a particular antigen site Polyclonal – multiple antibodies that attack different antigen sites May vary over time Monoclonal antibodies - designed to attack only one site on an antigen

11. Process of producing monoclonals (p.335) Inject mouse with a particular antigen Mouse spleen cells produce antibodies Spleen cells removed and fused to cancer cells Combined cells are called hybridoma cells Hybridoma cells allowed to multiply and are screened for antibody activity

12. Process continued Hybridoma that bear antibody activity of interest are selected, removed and cultured Produce identical monoclonal antibodies in endless supply Used to offer immunoassay test for certain drugs and semen material Current and most well known use of monoclonal antibodies is Rituxin (cancer treatment)

13. 12.1 Questions 1. Who discovered that blood is distinguishable by its group or type? 2. What blood factors are the most important for properly matching a donor and recipient for a transfusion? 3. What technique supplanted blood typing for associating bloodstain evidence with a particular individual? 4. What is plasma? What percentage of blood content does plasma account for? 5. Which of the following types of cells are not contained in plasma? A. Phagocytes B. Leukocytes C. Erthyrocytes D. Platelets 6. What are antigens and antibodies? What part of the blood contains antibodies? 7. Describe how antibodies and antigens determine one’s A-B-O blood type. 8. What is the fourth important antigen other than A, B, and O?