Table 1.
Overview of sialic acid linkages in the respiratory tract, the presence of Neu5Gc, and the presence of an intact CMAH gene in different animal models. +: high levels, -: low levels, --: not detected.
| Animal Model | Sialic Acid Linkage in the Respiratory Tract | Neu5Gc Detected | Intact CMAH Gene [4] | |
|---|---|---|---|---|
| α2,3 | α2,6 | |||
| Mouse | + [1] | - [1,16] |
Yes [6,9,10,11,12,13,14,15,89,90] Yes (Figure 2) |
Yes |
| Ferret | + [17] - (upper respiratory tract) [1] + (lung) [1] |
+ [17] + (upper respiratory tract) [1] - (lung) [1] |
No [17,18,19] No (Figure 2) |
No |
| Guinea pig | + (nasal tract, trachea) [91] + (lung) [91] |
+ (nasal tract, trachea) [91] - (lung) [91] |
Yes [9,92] Yes (Figure 2) |
Yes |
| Rat | + (trachea) [93] -- (lung) [93] |
+ (trachea) [93] - (lung) [93] |
Yes [9,94] | Yes |
| Syrian hamster | + [32] | + [32] | Yes (Figure 2) | Yes |
| Tree shrew | + [95] - (nasal tract, trachea) [43] + (lung) [43] |
+ [95] + (nasal tract, trachea) [43] - (lung) [43] |
Yes [95] | Yes |
| Swine | - [1,96] + (nasal tract) [97] - (trachea) [97] + (lung) [97,98] |
+ [1,96] - (nasal tract) [97] + (trachea) [97] + (lung) [97,98] |
Yes [96,98,99,100,101,102] Yes, 53% [103] Yes, 9–14% [104] Yes (Figure 2) |
Yes |
| Marmoset | + [45] | -- [45] | No [105] | No |
| Macaque | Unknown | Unknown | Yes [9,106] | Yes |
| Dog | + [107] | - [3,107] | No [28,88,108] Yes [88,89,109,110] |
Yes |
| Horse | + [1,107,111] | -- [3,107,111] | Yes [3,8,108] | Yes |