1. Immunological Pregnancy Testing
ELISA
What does it stand for?

2. Human Chorionic Gonadotropin (hCG)
= glycoprotein hormone
Trophoblast (= embryo) cells produce hCG, structurally similar to LH. Purpose?
Detectable in urine 6-8 days after conception
Old ways of detection?

3. Early Pregnancy Tests
Time consuming. Patient’s urine injected into female laboratory rabbit.
High concentrations of hCG  ovulation and development of the rabbit's uterus.
”The rabbit died” meant women is pregnant.  misnomer!

4. ELISA – the New Way of Pregnancy Testing
ELISA and the use of antibodies
How do you make antibodies?
What are conjugated antibodies?
Indirect Sandwich Assay

5. Indirect Sandwich ELISA uses two antibodies ( more sensitive)
Inactivated substrate
Secondary antibody conjugated to enzyme (e.g.: HRP)
Activated substrate changes color
Sandwich assay: measures amount of antigen between two layers of antibodies (most common case of indirect ELISA)
Target protein (hCG)
Primary antibody
Need picture of this type of assay
Surface molecules of ELISA plate plastic wells

6. Production of 1 and 2 Antibodies
Inject rabbit (mouse, goat etc.) with a human protein (specific ab / human hormone etc.)
What does rabbit do?
Polyclonal antibodies: mixed population of antibodies (produced by many clones) that recognize numerous epitopes
Monoclonal antibodies: bind to only 1 epitope

7. Monoclonal Antibody Production

8. 96-well microtiter plate
hCG ELISA
Review only 1st part