Quantitative protein analysis by immunodiffusion

• US 4,244,803 A
• Filed: 11/27/1979
• Issued: 01/13/1981
• Est. Priority Date: 11/27/1979
• Status: Expired due to Term

• Current Assignee: Frederick J. Aladjem, Padmasini K. Ayengar
• Original Assignee: Frederick J. Aladjem, Padmasini K. Ayengar
• Inventors: Aladjem, Frederick J., Ayengar, Padmasini K.
• Primary Examiner(s): Prescott, Arthur C.
• Application Number:
  US06/097,931
• Time in Patent Office: 413 Days
• Field of Search: 204/180 G, 204/180 S, 204/299 R, 23/230 B, 424/12, 356/72, 356/39, 356/402, 356/344
• US Class Current: 422/82.01
• CPC Class Codes: G01N 27/44721 by optical means
• CPC Class Codes: G01N 33/561 Immunoelectrophoresis
• CPC Class Codes: G01N 33/68 involving proteins, peptides or amino acids involving lipoproteins G01N33/92
• CPC Class Codes: Y10S 436/805 Optical property

Abstract

Methods and apparatus are described by which immunochemical procedures such as immunodiffusion and immunoelectrophoresis can be used to provide quantitative measurement of the concentration of individual proteins in fluids such as serum, spinal fluid, tissue extracts and the like. That is accomplished typically by photooptically scanning the zones of precipitation which are produced, in parallel with those of standard preparations containing known concentrations of the proteins to be determined; deriving from the arrays of measurements of the precipitation zones selected parameters; and comparing the parameter values of the experimental and reference preparations. The zone measurements are preferably made and recorded electronically, with suitable digital manipulation of the resulting video values at a plurality of selected positions for each zone.

Claims

1. Apparatus for obtaining a quantitative measure of the concentration of a protein in an antigen sample, comprising

means for supporting and illuminating a plate carrying a precipitation zone due to immunoelectrophoresis of said antigen sample with an antibody specific to said protein,

photoresponsive means for extracting a plurality of electrical signals representing the light intensity at positions on said plate which correspond to respective sets of position representing signals,

and electronic means for supplying to said photoresponsive means sets of position representing signals corresponding to positions in selected respective spatial relationship to said zone, and for deriving from the resulting light intensity representing signals the corresponding value of a parameter which varies in characteristic manner with said protein concentration.

2. Apparatus according to claim 1 wherein said electronic means include

means for supplying automatically to said photoresponsive means a series of sets of position representing signals which correspond to a two-dimensional array of positions distributed partly within and partly outside the zone,

and memory means for storing the resulting light representing signals together with position signals representing the position to which each light representing signal corresponds.

3. Apparatus according to claim 1, including

also

means for producing a two-dimensional visual display of said light representing signals,

said electronic means including

manually controllable means for developing a set of position representing signals corresponding to a selected position on said display,

and means for producing in digital form the light representing signal corresponding to the so developed position representing signals.

4. Apparatus for obtaining a quantitative measure of the concentration of an antigen in an antigen containing sample which has been subjected to immunodiffusion with an antibody specific to said antigen, the antigen and antibody diffusing through a supporting medium from respective sources mutually spaced along an axis and reacting to form at least one elongated precipitation zone of limited length;

said apparatus comprising

means for automatically scanning the supporting medium to develop electrical signals representing light intensity at respective positions of a two-dimensional array distributed partly within the zone and partly outside the zone, each light representing signal being associated with electrical position representing signals identifying the corresponding position in said array,

and means responsive jointly to position representing signals and the corresponding light representing signals for deriving the value of a selected parameter of the zone which varies in characteristic manner with said antigen concentration.

5. Apparatus according to claim 4 including means for causing said scanning means to repeat said scanning action intermittently, and means for associating electrical time signals with said light representing signals.

6. Apparatus for obtaining a quantitative measure of the concentration of an antigen in an antigen containing sample by subjecting the sample to immunodiffusion with an antibody source containing an antibody specific to said antigen, said reactants diffusing in a supporting medium from respective antigen and antibody wells to produce a precipitation zone;

said apparatus comprising

photoresponsive means for scanning the wells and the supporting medium to develop electrical signals representing light intensity at respective positions, each light representing signal being associated with electrical position representing signals identifying the corresponding position,

dispensing means for dispensing antigen and antibody containing solutions selectively to the respective wells in response to electrical command signals,

and control means responsive jointly to the light representing signals and the position representing signals and having one mode of operation for producing operative position of the dispensing means relative to each individual well and for supplying a command signal to the dispensing means to supply that well with a selected reagent,

said control means having another mode of operation for deriving electronically from the light representing signals and the position representing signals the corresponding value of a selected zone parameter which varies in characteristic manner with said antigen concentration.

7. Apparatus according to claim 6, said control means, when in said one mode, including means for deriving signals representing the position of each well, and being responsive to such well position signals for producing operative position of the dispensing means.

8. Apparatus according to claim 6 including

means associated with said control means, when in said one mode, for comparing the relative positions of said wells with predetermined standard relative well positions to detect deviations therefrom,

and means associated with said control means, when in said other mode, for compensating for such deviations during said parameter derivation.