Immunohistochemistry (IHC) Services

Immunohistochemistry answers questions that homogenate-based methods cannot, because it preserves spatial information. A lysate reports the average across an entire tumor. It cannot distinguish uniform expression from intense focal expression, cannot establish whether immune effector cells entered the tumor or remained at its margin, and cannot show whether proliferation and cell death are distributed evenly or confined to particular regions. Those distinctions are frequently the difference between two opposite interpretations of the same average.

Altogen Labs provides immunohistochemistry on tumor and tissue collected from in vivo studies, with staining, imaging, and quantification performed against protocol-defined criteria. To discuss a staining panel, request a quote.

What is measured

Common endpoints include proliferation and apoptosis indices, target expression and its distribution within the tumor, immune cell infiltration by subtype, vascular density, and markers of treatment-induced change. In immuno-oncology studies, quantification of CD8-positive infiltration, CD4-positive density, tumor architecture, and immune spatial distribution is a standard part of the secondary endpoint panel.

Spatial analysis is where the method earns its place. Quantifying effector cells separately in the tumor core and at the invasive margin distinguishes genuine infiltration from peripheral accumulation, and an agent that increases total intratumoral immune cells without changing their distribution has produced a different biological effect from one that drives penetration into the tumor mass.

Antibody validation and controls

An immunohistochemistry result is only as reliable as the antibody and the controls run alongside it. Antibodies are validated for the target, species, and fixation condition in use, since performance in one fixation protocol does not transfer to another. Positive and negative control tissue is run with each batch, and isotype or omission controls establish the contribution of non-specific binding to the observed signal.

Where a scoring system is applied, scoring criteria are defined before slides are read, and reading is performed blinded to treatment group where the endpoint is subjective. These are not formalities; unblinded scoring against undefined criteria is the most common way an immunohistochemistry endpoint produces a result that does not replicate.

Quantification

Quantification approach is selected for the endpoint. Positive cell counting suits discrete nuclear or membrane markers. Area-based quantification suits diffuse cytoplasmic or matrix staining. Intensity scoring suits markers where the amount rather than the presence of signal is informative. Region of interest selection is defined by rule rather than chosen per slide, since selecting fields after seeing them introduces bias that no subsequent statistical treatment removes.

Applied examples

Immune infiltration. Tumors from a checkpoint inhibitor study are stained for CD8 and a proliferation marker, with infiltrating cell density quantified separately in core and margin regions, establishing whether treatment drove penetration rather than peripheral accumulation.

Proliferation and apoptosis. Treated and control tumors are assessed for proliferation index and apoptotic index in matched regions, distinguishing a cytostatic effect from a cytotoxic one in tissue rather than inferring it from the growth curve.

Target distribution. A tumor is stained for the drug target before a study is designed, establishing whether expression is uniform or focal, which determines whether a homogenate-based pharmacodynamic endpoint will be interpretable.

Tissue handling and reporting

Fixation time, processing, and sectioning conditions are controlled and recorded, since over-fixation and under-fixation both alter epitope accessibility and a staining difference between groups can originate in handling rather than biology. Tissue destined for immunohistochemistry is identified at necropsy and fixed accordingly, with separate aliquots taken where the same tissue must also support molecular endpoints. Reports include representative images, the quantification method, the scoring criteria applied, and per-animal values rather than group means alone.

Send target, species, and tissue type, or request a quote.