Flow cytometry evaluation of biological material for unassociated virus-size particles

A flow cytometry method for evaluating a biological material sample for the presence of unassociated virus-size particles having a target epitope, the method comprising:

• subjecting to flow cytometry a fluid sample comprising at least a portion of the biological material sample and a fluorescent antibody stain with an antibody targeted to bind, directly or indirectly, with the target epitope to form unassociated labeled particles of virus size, the unassociated labeled particles including a said virus-size particle fluorescently labeled with the fluorescent antibody stain, the flow cytometry comprising:
• flowing the fluid sample through a flow cell of a flow cytometer;
• subjecting the fluid sample flowing through the flow cell to excitation radiation capable of causing a fluorescent emission response from the fluorescent antibody stain;
• and
• detecting radiation from the flow cell within a wavelength range of the fluorescent emission response and evaluating the detected radiation to identify detection events indicative of passage through the flow cell of the unassociated labeled particles;
• and
• the flow cytometry being in the absence of identification of the unassociated labeled particles using light scatter detection.

A flow cytometry method for evaluating a biological material sample for the presence of unassociated virus-size particles having a target epitope, the method comprising:

• preparing a fluid sample, the preparing the fluid sample comprising mixing biological material to be evaluated for presence of the unassociated particles with a fluorescent antibody stain with an antibody targeted to bind, directly or indirectly, with the target epitope to form unassociated labeled particles of virus size, the unassociated labeled particles including a said virus-size particle fluorescently labeled with the fluorescent antibody stain;
• subjecting to flow cytometry the fluid sample, the flow cytometry comprising:
• flowing the fluid sample through a flow cell of a flow cytometer;
• subjecting the fluid sample flowing through the flow cell to excitation radiation capable of causing a fluorescent emission response from the fluorescent antibody stain;
• and
• detecting radiation from the flow cell within a wavelength range of the fluorescent emission response and evaluating the detected radiation to identify detection events indicative of passage through the flow cell of the unassociated labeled particles;
• and
• after the mixing, not removing unbound said fluorescent antibody stain, not bound in the unassociated labeled particles, from the fluid sample prior to the flow cytometry.

A flow cytometry method for evaluating a biological material sample for the presence of unassociated virus-size particles having a target epitope, the method comprising:

• subjecting to flow cytometry a fluid sample comprising at least a portion of the biological material sample and a fluorescent antibody stain with an antibody targeted to bind, directly or indirectly, with the target epitope to form unassociated labeled particles of virus size, the unassociated labeled particles including a said virus-size particle fluorescently labeled with the fluorescent antibody stain, the flow cytometry comprising:
• flowing the fluid sample through a flow cell of a flow cytometer;
• subjecting the fluid sample flowing through the flow cell to excitation radiation capable of causing a fluorescent emission response from the fluorescent antibody stain;
• and
• detecting radiation from the flow cell within a wavelength range of the fluorescent emission response and evaluating the detected radiation to identify detection events indicative of passage through the flow cell of the unassociated labeled particles;
• and
• the fluid sample as fed to the flow cytometer comprising a concentration of the fluorescent antibody stain, not bound in the unassociated labeled particles, in a range of from 0.5 microgram per milliliter to 10 micrograms per milliliter.