An antibody comprising: (a) a first polypeptide comprising VH, CH1, hinge, CH2, and CH3 domains positioned relative to each other in an N-terminal to C-terminal direction: VH-CH1-hinge-CH2-CH3 and a first coiled coil domain C-terminally linked to the CH3 domain by a linker, wherein the first CC comprises a heptad repeat of Formula I: (X 1 X 2 X 3 X 4 X 5 X 6 X 7) n (Formula I), wherein X 1 is a hydrophobic amino acid residue or Asparagine, X 2, X 3, and X 6 are each any amino acid residue, X 4 is a hydrophobic amino acid residue, and X 5 and X 7 are each a charged amino acid residue; and (b) a second polypeptide comprising VH, CH1, hinge, CH2, and CH3 domains positioned relative to each other in an N-terminal to C-terminal direction: VH-CH1-hinge-CH2-CH3 and a second coiled coil C-terminally linked to the CH3 domain by a linker, wherein the second CC comprises a heptad repeat of Formula II: (X' 1 X' 2 X' 3 X' 4 X' 5 X' 6 X' 7) n (Formula II), wherein X' 1 is a hydrophobic amino acid residue or Asparagine, X' 2, X' 3, and X' 6 are each any amino acid residue, X' 4 is a hydrophobic amino acid residue, and X' 5 and X' 7 are each a charged amino acid residue; wherein n in Formula I and II is greater than or equal to 2; and wherein, in each heptad repeat, the first CC comprises an X 5 residue that is opposite in charge to the X' 7 residue in the second CC and the first CC comprises an X 7 residue that is opposite in charge to the X' 5 residue in the second CC, and wherein the linker is proteolytic cleavable by one or more of the endopeptidases selected from the group consisting of: furin, thrombin, genenase, Lys-C, Arg-C, Asp-N, Glu-C, Factor Xa, Tobacco Etch Virus Protease, enterokinase, Human Rhinovirus C3 protease (HRV C3), and Kininogenase, and wherein the antibody further comprises a third polypeptide, wherein the third polypeptide comprises a VL domain. (a) a first polypeptide comprising VH, CH1, hinge, CH2, and CH3 domains positioned relative to each other in an N-terminal to C-terminal direction: VH-CH1-hinge-CH2-CH3 and a first coiled coil domain C-terminally linked to the CH3 domain by a linker, wherein the first CC comprises a heptad repeat of Formula I: (X 1 X 2 X 3 X 4 X 5 X 6 X 7) n (Formula I), wherein X 1 is a hydrophobic amino acid residue or Asparagine, X 2, X 3, and X 6 are each any amino acid residue, X 4 is a hydrophobic amino acid residue, and X 5 and X 7 are each a charged amino acid residue; and (b) a second polypeptide comprising VH, CH1, hinge, CH2, and CH3 domains positioned relative to each other in an N-terminal to C-terminal direction: VH-CH1-hinge-CH2-CH3 and a second coiled coil C-terminally linked to the CH3 domain by a linker, wherein the second CC comprises a heptad repeat of Formula II: (X' 1 X' 2 X' 3 X' 4 X' 5 X' 6 X' 7) n (Formula II), wherein X' 1 is a hydrophobic amino acid residue or Asparagine, X' 2, X' 3, and X' 6 are each any amino acid residue, X' 4 is a hydrophobic amino acid residue, and X' 5 and X' 7 are each a charged amino acid residue; (X 1 X 2 X 3 X 4 X 5 X 6 X 7) n (Formula I), wherein X 1 is a hydrophobic amino acid residue or Asparagine, X 2, X 3, and X 6 are each any amino acid residue, X 4 is a hydrophobic amino acid residue, and X 5 and X 7 are each a charged amino acid residue; and (b) a second polypeptide comprising VH, CH1, hinge, CH2, and CH3 domains positioned relative to each other in an N-terminal to C-terminal direction: VH-CH1-hinge-CH2-CH3 and a second coiled coil C-terminally linked to the CH3 domain by a linker, wherein the second CC comprises a heptad repeat of Formula II: X 1 is a hydrophobic amino acid residue or Asparagine, X 2, X 3, and X 6 are each any amino acid residue, X 4 is a hydrophobic amino acid residue, and X 5 and X 7 are each a charged amino acid residue; and (X' 1 X' 2 X' 3 X' 4 X' 5 X' 6 X' 7) n (Formula II), wherein X' 1 is a hydrophobic amino acid residue or Asparagine, X' 2, X' 3, and X' 6 are each any amino acid residue, X' 4 is a hydrophobic amino acid residue, and X' 5 and X' 7 are each a charged amino acid residue; X' 1 is a hydrophobic amino acid residue or Asparagine, X' 2, X' 3, and X' 6 are each any amino acid residue, X' 4 is a hydrophobic amino acid residue, and X' 5 and X' 7 are each a charged amino acid residue;