Table 3. Available validation data for the antibodies used in the studies described in this review in accordance to the pillars defined by the Antibodypedia validation initiative (Uhlen et al., 2016).
Provider refers to the information found in the website of the company. IB: Immunoblot. IHC: Immunohistochemistry. IF: Immunofluorescence. 
Enhanced validation, 
Supportive validation, 
No data available, + Positive detection, +/- Weak detection, - Absence of detection.
| Method | Antibodypedia | Provider | Additional information | |
|---|---|---|---|---|
| Ab15348 (or GTX15348) Immunogen: 788-805aa |
IB |  |
+ Testis, intestines, lung, Calu-3 - Breast |
 |
| IHC |  |
+ Testis, kidney, aorta and lung | + Intestine, heart, stomach, spleen (Independent antibody validation) (Lee et al., 2020) +, +/-, - Lung. Increased in COPD and smokers (correlation with mRNA) (Leung et al., 2020; Muus et al., 2020; Lee et al., 2020) |
|
| IF |  |
 |
 |
|
| MAB933 Immunogen: 18-74aa |
IB |  |
+ Kidney - NSO cells |
+ Vero E6 cells - CHO cells (Jia et al., 2005) |
| IHC |  |
+ Kidney | + Orthogonal (RNA) and independent antibody validation +/-, - Lung (Hikmet et al., 2020; Aguiar et al., 2020; Muus et al., 2020; Lee et al., 2020) |
|
| IF |  |
 |
+ ALI-cultured ciliated airway epithelial cells (Martinez-Anton et al., 2013) | |
| AF933 Immunogen: 18-74aa |
IB |  |
+ Ovary, testis and kidney | + Airway and distal lung, ALI-cultured airway epithelial cells (correlation with mRNA levels), Calu-3 and Caco-2 cells (Liao et al., 2013; Smith et al., 2020) - A549 (expected), Huh-7 cells (Liao et al., 2013; Smith et al., 2020) |
| IHC |  |
+ Kidney | + Testis, stomach, intestine (Independent antibody validation) +/-, - Lung (Ren et al., 2006; Muus et al., 2020; Lee et al., 2020) |
|
| IF |  |
 |
 |
|
| HPA000288 Immunogen: 1-111aa |
IB |  |
+ Kidney, but several bands |  |
| IHC |  |
+ Intestine and kidney. - Tonsil |
+ Orthogonal (RNA) and independent antibody validation +/-, - Lung (Uhlén et al., 2015; Hikmet et al., 2020; Lee et al., 2020) |
|
| IF |  |
 |
 |
|
|
Ab108252 Immunogen: 200-300aa |
IB |  |
+ Testis, kidney, lung, HepG2, Caco-2 - A549 cells |
 |
| IHC |  |
+ Kidney |  |
|
| IF |  |
 |
 |
|
|
Ab239924 Immunogen: 200-300aa |
IB |  |
+ Testis, kidney | + ACE2 transfected A459 - Non transfected A549 cells (Blanco-Melo et al., 2020) |
| IHC |  |
+ Testis, kidney | + Intestine, heart, stomach, spleen (Independent antibody validation), +/- Lung (Lee et al., 2020) | |
| IF |  |
 |
 |
|
| NBP2-67692 Immunogen: 200-300aa |
IB |  |
+ Kidney |  |
| IHC |  |
+ Kidney | + Testis and intestine (Independent antibody validation) - Lung (Lee et al., 2020) |
|
| IF |  |
+ HepG2, MCF-7, 293 cells |  |
|
| Anti-ACE2489
Immunogen: 489-508aa |
IB |  |
+ACE2 transfected CHO cells - Non transfected CHO cells |
 |
| IHC |  |
 |
+ Heart (No staining with secondary antibody alone) (Qian et al., 2013) | |
| IF |  |
 |
 |
|
| Sc-20998 Immunogen: 631-805aa |
IB |  |
Antibody discontinued | Detection in rat tissue only (Sims et al., 2005) |
| IHC |  |
Antibody discontinued |  |
|
| IF |  |
Antibody discontinued |  |
|
| Homemade antibody Immunogen: 206-225aa |
IB |  |
 |
Detection in rat tissue only (Mossel et al., 2008) |
| IHC |  |
 |
 |
|
| IF |  |
 |
 |