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MLAB 1335 Immunology/Serology
Laboratory 5: Phagocytosis
Name _________________________
Date _______________ ____/10 points
Objectives
1. Describe the steps in the phagocytic process.
2. Prepare blood smears at the appropriate time intervals for demonstration of phagocytosis.
3. Observe the blood smear microscopically using the 100x oil immersion lens.
4. Identify white cells which have engulfed bacteria.
5. State two reasons why bacteria may not be observed on the blood smear.
Principle
A drop of whole blood is mixed with a drop of a bacterial culture. The specimen is incubated at room
temperature to demonstrate vacuolization of bacteria by leukocytes during the phagocytic process.
Materials
Glass test tubes
Microhematocrit tubes Slides
Hematology slide stainer
Lancets Alcohol swabs
Bacterial suspension
Kimwipes
Gauze
Small rubber bulb
0.5 McFarland standard
Procedure
1. Create a 0.5 McFarland standard concentration of the Staphylococcus species culture. Your instructor
will explain the McFarland standards.
2. Perform capillary puncture. NOTE: If you are also performing ABO collect a drop of blood into your
12x75 tube FIRST. Label the tube with your partners first and last name. Refer to MLAB 2360 Activity
5: ABO Blood Grouping Genetics for specific instructions.
3. Label 3 12 x 75 mm test tubes as follows: 0 minutes, 5 minutes, and 10 minutes. Label your tube with
your partners first and last name for the clinical I activity 5-ABO tubing.
4. Perform a capillary puncture and collect 3 heparinized microhematocrit tubes.
5. Attach the black rubber bulb to the capillary tube and dispense one drop of blood into the three tubes
labeled with minutes.
6. Dispense 5 drops into the ABO test tube.
7. Add one drop of Staphylococcus species culture to each tube with a disposable pipette.
8. Shake the tubes and make a blood smear immediately of the “0” minute tube.
9. Set a timer for 5 and 10 minutes. Make blood smears of these solutions at the times specified.
10. Stain the slides.
11. Carefully scan the blood smear for bacteria (intracellular and extracellular) on 100x oil. Look for
pseudo pod formation by the white blood cells. Record your observations in the chart.
Slide
Acceptable
Record your observations
Verified by
instructor
0 minute
5 minute
10
minute
Limitation to the procedure-If lymphocytes are the only WBC seen, the bacterial suspension was too heavy,
and the phagocytic cells destroyed themselves in an attempt to engulf the bacteria present.
Study Question
1. Fully explain the process of phagocytosis using your textbook, pages 9-12. (4 Points)